diff --git a/Preface.ipynb b/Preface.ipynb
index ba3b9a3..e092f2b 100644
--- a/Preface.ipynb
+++ b/Preface.ipynb
@@ -1,7 +1,7 @@
 {
  "metadata": {
   "name": "",
-  "signature": "sha256:0b133277ac85f975c916bc21148ad9bfba4634dc26c82d0842b53aee56e01439"
+  "signature": "sha256:1271401e3e500309f48f2586d911eb77b92fa00c7c1e66dfa6cb66278cada519"
  },
  "nbformat": 3,
  "nbformat_minor": 0,
@@ -9,11 +9,11 @@
   {
    "cells": [
     {
-     "cell_type": "markdown",
+     "cell_type": "heading",
+     "level": 1,
      "metadata": {},
      "source": [
-      "<center><h1>Kalman and Bayesian Filters in Python</h1></center>\n",
-      "<center><a href =\"http://nbviewer.ipython.org/urls/raw.github.com/rlabbe/Kalman-and-Bayesian-Filters-in-Python/master/toc.ipynb\">Table of Contents</a></center>"
+      "Preface"
      ]
     },
     {
@@ -31,92 +31,227 @@
      "metadata": {},
      "outputs": [
       {
-       "output_type": "stream",
-       "stream": "stdout",
-       "text": [
-        "Installed secnum.py. To use it, type:\n",
-        "  %load_ext secnum\n"
-       ]
-      },
-      {
-       "javascript": [
-        "console.log(\"Section numbering...\");\n",
+       "html": [
+        "<style>\n",
+        "@import url('http://fonts.googleapis.com/css?family=Source+Code+Pro');\n",
         "\n",
-        "function number_sections(threshold) {\n",
-        "\n",
-        "  var h1_number = 0;\n",
-        "  var h2_number = 0;\n",
-        "\n",
-        "  if (threshold === undefined) {\n",
-        "    threshold = 2;  // does nothing so far\n",
-        "  }\n",
-        "\n",
-        "  var cells = IPython.notebook.get_cells();\n",
-        "  \n",
-        "  for (var i=0; i < cells.length; i++) {\n",
-        "\n",
-        "    var cell = cells[i];\n",
-        "    if (cell.cell_type !== 'heading') continue;\n",
-        "    \n",
-        "    var level = cell.level;\n",
-        "    if (level > threshold) continue;\n",
-        "    \n",
-        "    if (level === 1) {\n",
-        "        \n",
-        "        h1_number ++;\n",
-        "        var h1_element = cell.element.find('h1');\n",
-        "        var h1_html = h1_element.html();\n",
-        "        \n",
-        "        console.log(\"h1_html: \" + h1_html);\n",
-        "\n",
-        "        var patt = /^[0-9]+\\.\\s(.*)/;   // section number at start of string\n",
-        "        var title = h1_html.match(patt);  // just the title\n",
-        "\n",
-        "        if (title != null) {  \n",
-        "          h1_element.html(h1_number + \". \" + title[1]);\n",
-        "        }\n",
-        "        else {\n",
-        "          h1_element.html(h1_number + \". \" + h1_html);\n",
-        "        }\n",
-        "        \n",
-        "        h2_number = 0;\n",
-        "        \n",
+        "    div.cell{\n",
+        "        width: 850px;\n",
+        "        margin-left: 0% !important;\n",
+        "        margin-right: auto;\n",
         "    }\n",
-        "    \n",
-        "    if (level === 2) {\n",
-        "    \n",
-        "        h2_number ++;\n",
-        "        \n",
-        "        var h2_element = cell.element.find('h2');\n",
-        "        var h2_html = h2_element.html();\n",
-        "\n",
-        "        console.log(\"h2_html: \" + h2_html);\n",
-        "\n",
-        "        \n",
-        "        var patt = /^[0-9]+\\.[0-9]+\\.\\s/;\n",
-        "        var result = h2_html.match(patt);\n",
-        "\n",
-        "        if (result != null) {\n",
-        "          h2_html = h2_html.replace(result, \"\");\n",
-        "        }\n",
-        "\n",
-        "        h2_element.html(h1_number + \".\" + h2_number + \". \" + h2_html);\n",
-        "        \n",
+        "    div.text_cell code {\n",
+        "        background: transparent;\n",
+        "        color: #000000;\n",
+        "        font-weight: 600;\n",
+        "        font-size: 13pt;\n",
+        "        font-style: bold;\n",
+        "        font-family:  'Source Code Pro', Consolas, monocco, monospace;\n",
+        "   }\n",
+        "    h1 {\n",
+        "        font-family: 'Open sans',verdana,arial,sans-serif;\n",
+        "\t}\n",
+        "\t\n",
+        "    div.input_area {\n",
+        "        background: #F6F6F9;\n",
+        "        border: 1px solid #586e75;\n",
         "    }\n",
-        "    \n",
-        "  }\n",
-        "  \n",
-        "}\n",
         "\n",
-        "number_sections();\n",
-        "\n",
-        "// $([IPython.evnts]).on('create.Cell', number_sections);\n",
-        "\n",
-        "$([IPython.events]).on('selected_cell_type_changed.Notebook', number_sections);\n",
-        "\n"
+        "    .text_cell_render h1 {\n",
+        "        font-weight: 200;\n",
+        "        font-size: 30pt;\n",
+        "        line-height: 100%;\n",
+        "        color:#c76c0c;\n",
+        "        margin-bottom: 0.5em;\n",
+        "        margin-top: 1em;\n",
+        "        display: block;\n",
+        "        white-space: wrap;\n",
+        "    } \n",
+        "    h2 {\n",
+        "        font-family: 'Open sans',verdana,arial,sans-serif;\n",
+        "    }\n",
+        "    .text_cell_render h2 {\n",
+        "        font-weight: 200;\n",
+        "        font-size: 20pt;\n",
+        "        font-style: italic;\n",
+        "        line-height: 100%;\n",
+        "        color:#c76c0c;\n",
+        "        margin-bottom: 0.5em;\n",
+        "        margin-top: 1.5em;\n",
+        "        display: block;\n",
+        "        white-space: nowrap;\n",
+        "    } \n",
+        "    h3 {\n",
+        "        font-family: 'Open sans',verdana,arial,sans-serif;\n",
+        "    }\n",
+        "    .text_cell_render h3 {\n",
+        "        font-weight: 300;\n",
+        "        font-size: 18pt;\n",
+        "        line-height: 100%;\n",
+        "        color:#d77c0c;\n",
+        "        margin-bottom: 0.5em;\n",
+        "        margin-top: 2em;\n",
+        "        display: block;\n",
+        "        white-space: nowrap;\n",
+        "    }\n",
+        "    h4 {\n",
+        "        font-family: 'Open sans',verdana,arial,sans-serif;\n",
+        "    }\n",
+        "    .text_cell_render h4 {\n",
+        "        font-weight: 300;\n",
+        "        font-size: 16pt;\n",
+        "        color:#d77c0c;\n",
+        "        margin-bottom: 0.5em;\n",
+        "        margin-top: 0.5em;\n",
+        "        display: block;\n",
+        "        white-space: nowrap;\n",
+        "    }\n",
+        "    h5 {\n",
+        "        font-family: 'Open sans',verdana,arial,sans-serif;\n",
+        "    }\n",
+        "    .text_cell_render h5 {\n",
+        "        font-weight: 300;\n",
+        "        font-style: normal;\n",
+        "        color: #1d3b84;\n",
+        "        font-size: 16pt;\n",
+        "        margin-bottom: 0em;\n",
+        "        margin-top: 1.5em;\n",
+        "        display: block;\n",
+        "        white-space: nowrap;\n",
+        "    }\n",
+        "    div.text_cell_render{\n",
+        "        font-family: 'Open sans',verdana,arial,sans-serif;\n",
+        "        line-height: 135%;\n",
+        "        font-size: 110%;\n",
+        "        width:750px;\n",
+        "        margin-left:auto;\n",
+        "        margin-right:auto;\n",
+        "        text-align:justify;\n",
+        "        text-justify:inter-word;\n",
+        "    }\n",
+        "    div.output_subarea.output_text.output_pyout {\n",
+        "        overflow-x: auto;\n",
+        "        overflow-y: scroll;\n",
+        "        max-height: 300px;\n",
+        "    }\n",
+        "    div.output_subarea.output_stream.output_stdout.output_text {\n",
+        "        overflow-x: auto;\n",
+        "        overflow-y: scroll;\n",
+        "        max-height: 300px;\n",
+        "    }\n",
+        "    code{\n",
+        "      font-size: 70%;\n",
+        "    }\n",
+        "    .rendered_html code{\n",
+        "    background-color: transparent;\n",
+        "    }\n",
+        "    ul{\n",
+        "        margin: 2em;\n",
+        "    }\n",
+        "    ul li{\n",
+        "        padding-left: 0.5em; \n",
+        "        margin-bottom: 0.5em; \n",
+        "        margin-top: 0.5em; \n",
+        "    }\n",
+        "    ul li li{\n",
+        "        padding-left: 0.2em; \n",
+        "        margin-bottom: 0.2em; \n",
+        "        margin-top: 0.2em; \n",
+        "    }\n",
+        "    ol{\n",
+        "        margin: 2em;\n",
+        "    }\n",
+        "    ol li{\n",
+        "        padding-left: 0.5em; \n",
+        "        margin-bottom: 0.5em; \n",
+        "        margin-top: 0.5em; \n",
+        "    }\n",
+        "    ul li{\n",
+        "        padding-left: 0.5em; \n",
+        "        margin-bottom: 0.5em; \n",
+        "        margin-top: 0.2em; \n",
+        "    }\n",
+        "    a:link{\n",
+        "       font-weight: bold;\n",
+        "       color:#447adb;\n",
+        "    }\n",
+        "    a:visited{\n",
+        "       font-weight: bold;\n",
+        "       color: #1d3b84;\n",
+        "    }\n",
+        "    a:hover{\n",
+        "       font-weight: bold;\n",
+        "       color: #1d3b84;\n",
+        "    }\n",
+        "    a:focus{\n",
+        "       font-weight: bold;\n",
+        "       color:#447adb;\n",
+        "    }\n",
+        "    a:active{\n",
+        "       font-weight: bold;\n",
+        "       color:#447adb;\n",
+        "    }\n",
+        "    .rendered_html :link {\n",
+        "       text-decoration: underline; \n",
+        "    }\n",
+        "    .rendered_html :hover {\n",
+        "       text-decoration: none; \n",
+        "    }\n",
+        "    .rendered_html :visited {\n",
+        "      text-decoration: none;\n",
+        "    }\n",
+        "    .rendered_html :focus {\n",
+        "      text-decoration: none;\n",
+        "    }\n",
+        "    .rendered_html :active {\n",
+        "      text-decoration: none;\n",
+        "    }\n",
+        "    .warning{\n",
+        "        color: rgb( 240, 20, 20 )\n",
+        "    } \n",
+        "    hr {\n",
+        "      color: #f3f3f3;\n",
+        "      background-color: #f3f3f3;\n",
+        "      height: 1px;\n",
+        "    }\n",
+        "    blockquote{\n",
+        "      display:block;\n",
+        "      background: #fcfcfc;\n",
+        "      border-left: 5px solid #c76c0c;\n",
+        "      font-family: 'Open sans',verdana,arial,sans-serif;\n",
+        "      width:680px;\n",
+        "      padding: 10px 10px 10px 10px;\n",
+        "      text-align:justify;\n",
+        "      text-justify:inter-word;\n",
+        "      }\n",
+        "      blockquote p {\n",
+        "        margin-bottom: 0;\n",
+        "        line-height: 125%;\n",
+        "        font-size: 100%;\n",
+        "      }\n",
+        "</style>\n",
+        "<script>\n",
+        "    MathJax.Hub.Config({\n",
+        "                        TeX: {\n",
+        "                           extensions: [\"AMSmath.js\"]\n",
+        "                           },\n",
+        "                tex2jax: {\n",
+        "                    inlineMath: [ ['$','$'], [\"\\\\(\",\"\\\\)\"] ],\n",
+        "                    displayMath: [ ['$$','$$'], [\"\\\\[\",\"\\\\]\"] ]\n",
+        "                },\n",
+        "                displayAlign: 'center', // Change this to 'center' to center equations.\n",
+        "                \"HTML-CSS\": {\n",
+        "                    styles: {'.MathJax_Display': {\"margin\": 4}}\n",
+        "                }\n",
+        "        });\n",
+        "</script>\n"
        ],
        "metadata": {},
-       "output_type": "display_data"
+       "output_type": "pyout",
+       "prompt_number": 1,
+       "text": [
+        "<IPython.core.display.HTML at 0x7effb6ec4d90>"
+       ]
       }
      ],
      "prompt_number": 1
@@ -251,235 +386,11 @@
      ]
     },
     {
-     "cell_type": "code",
-     "collapsed": false,
-     "input": [
-      "#format the book\n",
-      "import book_format\n",
-      "book_format.load_style()"
-     ],
-     "language": "python",
+     "cell_type": "markdown",
      "metadata": {},
-     "outputs": [
-      {
-       "html": [
-        "<style>\n",
-        "    div.cell{\n",
-        "        width: 850px;\n",
-        "        margin-left: 0% !important;\n",
-        "        margin-right: auto;\n",
-        "    }\n",
-        "    div.text_cell code {\n",
-        "        background: #F6F6F9;\n",
-        "        color: #0000FF;\n",
-        "   }\n",
-        "    h1 {\n",
-        "        font-family: 'Open sans',verdana,arial,sans-serif;\n",
-        "\t}\n",
-        "\t\n",
-        "    div.input_area {\n",
-        "        background: #F6F6F9;\n",
-        "        border: 1px solid #586e75;\n",
-        "    }\n",
-        "\n",
-        "    .text_cell_render h1 {\n",
-        "        font-weight: 200;\n",
-        "        font-size: 36pt;\n",
-        "        line-height: 100%;\n",
-        "        color:#c76c0c;\n",
-        "        margin-bottom: 0.5em;\n",
-        "        margin-top: 1em;\n",
-        "        display: block;\n",
-        "        white-space: wrap;\n",
-        "    } \n",
-        "    h2 {\n",
-        "        font-family: 'Open sans',verdana,arial,sans-serif;\n",
-        "    }\n",
-        "    .text_cell_render h2 {\n",
-        "        font-weight: 200;\n",
-        "        font-size: 20pt;\n",
-        "        font-style: italic;\n",
-        "        line-height: 100%;\n",
-        "        color:#c76c0c;\n",
-        "        margin-bottom: 1.5em;\n",
-        "        margin-top: 0.5em;\n",
-        "        display: block;\n",
-        "        white-space: nowrap;\n",
-        "    } \n",
-        "    h3 {\n",
-        "        font-family: 'Open sans',verdana,arial,sans-serif;\n",
-        "    }\n",
-        "    .text_cell_render h3 {\n",
-        "        font-weight: 300;\n",
-        "        font-size: 18pt;\n",
-        "        line-height: 100%;\n",
-        "        color:#d77c0c;\n",
-        "        margin-bottom: 0.5em;\n",
-        "        margin-top: 2em;\n",
-        "        display: block;\n",
-        "        white-space: nowrap;\n",
-        "    }\n",
-        "    h4 {\n",
-        "        font-family: 'Open sans',verdana,arial,sans-serif;\n",
-        "    }\n",
-        "    .text_cell_render h4 {\n",
-        "        font-weight: 300;\n",
-        "        font-size: 16pt;\n",
-        "        color:#d77c0c;\n",
-        "        margin-bottom: 0.5em;\n",
-        "        margin-top: 0.5em;\n",
-        "        display: block;\n",
-        "        white-space: nowrap;\n",
-        "    }\n",
-        "    h5 {\n",
-        "        font-family: 'Open sans',verdana,arial,sans-serif;\n",
-        "    }\n",
-        "    .text_cell_render h5 {\n",
-        "        font-weight: 300;\n",
-        "        font-style: normal;\n",
-        "        color: #1d3b84;\n",
-        "        font-size: 16pt;\n",
-        "        margin-bottom: 0em;\n",
-        "        margin-top: 1.5em;\n",
-        "        display: block;\n",
-        "        white-space: nowrap;\n",
-        "    }\n",
-        "    div.text_cell_render{\n",
-        "        font-family: 'Open sans',verdana,arial,sans-serif;\n",
-        "        line-height: 135%;\n",
-        "        font-size: 125%;\n",
-        "        width:750px;\n",
-        "        margin-left:auto;\n",
-        "        margin-right:auto;\n",
-        "        text-align:justify;\n",
-        "        text-justify:inter-word;\n",
-        "    }\n",
-        "    div.output_subarea.output_text.output_pyout {\n",
-        "        overflow-x: auto;\n",
-        "        overflow-y: scroll;\n",
-        "        max-height: 300px;\n",
-        "    }\n",
-        "    div.output_subarea.output_stream.output_stdout.output_text {\n",
-        "        overflow-x: auto;\n",
-        "        overflow-y: scroll;\n",
-        "        max-height: 300px;\n",
-        "    }\n",
-        "    code{\n",
-        "      font-size: 70%;\n",
-        "    }\n",
-        "    .rendered_html code{\n",
-        "    background-color: transparent;\n",
-        "    }\n",
-        "    ul{\n",
-        "        margin: 2em;\n",
-        "    }\n",
-        "    ul li{\n",
-        "        padding-left: 0.5em; \n",
-        "        margin-bottom: 0.5em; \n",
-        "        margin-top: 0.5em; \n",
-        "    }\n",
-        "    ul li li{\n",
-        "        padding-left: 0.2em; \n",
-        "        margin-bottom: 0.2em; \n",
-        "        margin-top: 0.2em; \n",
-        "    }\n",
-        "    ol{\n",
-        "        margin: 2em;\n",
-        "    }\n",
-        "    ol li{\n",
-        "        padding-left: 0.5em; \n",
-        "        margin-bottom: 0.5em; \n",
-        "        margin-top: 0.5em; \n",
-        "    }\n",
-        "    ul li{\n",
-        "        padding-left: 0.5em; \n",
-        "        margin-bottom: 0.5em; \n",
-        "        margin-top: 0.2em; \n",
-        "    }\n",
-        "    a:link{\n",
-        "       font-weight: bold;\n",
-        "       color:#447adb;\n",
-        "    }\n",
-        "    a:visited{\n",
-        "       font-weight: bold;\n",
-        "       color: #1d3b84;\n",
-        "    }\n",
-        "    a:hover{\n",
-        "       font-weight: bold;\n",
-        "       color: #1d3b84;\n",
-        "    }\n",
-        "    a:focus{\n",
-        "       font-weight: bold;\n",
-        "       color:#447adb;\n",
-        "    }\n",
-        "    a:active{\n",
-        "       font-weight: bold;\n",
-        "       color:#447adb;\n",
-        "    }\n",
-        "    .rendered_html :link {\n",
-        "       text-decoration: underline; \n",
-        "    }\n",
-        "    .rendered_html :hover {\n",
-        "       text-decoration: none; \n",
-        "    }\n",
-        "    .rendered_html :visited {\n",
-        "      text-decoration: none;\n",
-        "    }\n",
-        "    .rendered_html :focus {\n",
-        "      text-decoration: none;\n",
-        "    }\n",
-        "    .rendered_html :active {\n",
-        "      text-decoration: none;\n",
-        "    }\n",
-        "    .warning{\n",
-        "        color: rgb( 240, 20, 20 )\n",
-        "    } \n",
-        "    hr {\n",
-        "      color: #f3f3f3;\n",
-        "      background-color: #f3f3f3;\n",
-        "      height: 1px;\n",
-        "    }\n",
-        "    blockquote{\n",
-        "      display:block;\n",
-        "      background: #fcfcfc;\n",
-        "      border-left: 5px solid #c76c0c;\n",
-        "      font-family: 'Open sans',verdana,arial,sans-serif;\n",
-        "      width:680px;\n",
-        "      padding: 10px 10px 10px 10px;\n",
-        "      text-align:justify;\n",
-        "      text-justify:inter-word;\n",
-        "      }\n",
-        "      blockquote p {\n",
-        "        margin-bottom: 0;\n",
-        "        line-height: 125%;\n",
-        "        font-size: 100%;\n",
-        "      }\n",
-        "</style>\n",
-        "<script>\n",
-        "    MathJax.Hub.Config({\n",
-        "                        TeX: {\n",
-        "                           extensions: [\"AMSmath.js\"]\n",
-        "                           },\n",
-        "                tex2jax: {\n",
-        "                    inlineMath: [ ['$','$'], [\"\\\\(\",\"\\\\)\"] ],\n",
-        "                    displayMath: [ ['$$','$$'], [\"\\\\[\",\"\\\\]\"] ]\n",
-        "                },\n",
-        "                displayAlign: 'center', // Change this to 'center' to center equations.\n",
-        "                \"HTML-CSS\": {\n",
-        "                    styles: {'.MathJax_Display': {\"margin\": 4}}\n",
-        "                }\n",
-        "        });\n",
-        "</script>\n"
-       ],
-       "metadata": {},
-       "output_type": "pyout",
-       "prompt_number": 1,
-       "text": [
-        "<IPython.core.display.HTML at 0x2c2e590>"
-       ]
-      }
-     ],
-     "prompt_number": 1
+     "source": [
+      "rlabbejr@gmail.com"
+     ]
     }
    ],
    "metadata": {}
diff --git a/build_book.sh b/build_book.sh
index 41370a8..5db96d5 100755
--- a/build_book.sh
+++ b/build_book.sh
@@ -2,7 +2,7 @@
 
 echo "merging book..."
 
-ipython nbmerge.py Preface.ipynb Signals_and_Noise.ipynb g-h_filter.ipynb discrete_bayes.ipynb Gaussians.ipynb Kalman_Filters.ipynb Multidimensional_Kalman_Filters.ipynb Kalman_Filter_Math.ipynb Designing_Kalman_Filters.ipynb Extended_Kalman_Filters.ipynb Unscented_Kalman_Filter.ipynb > Kalman_and_Bayesian_Filters_in_Python.ipynb
+python merge_book.py > Kalman_and_Bayesian_Filters_in_Python.ipynb
 
 echo "creating pdf..."
 ipython nbconvert --to latex --template book --post PDF Kalman_and_Bayesian_Filters_in_Python.ipynb
diff --git a/g-h_filter.ipynb b/g-h_filter.ipynb
index 2459489..b54fdcb 100644
--- a/g-h_filter.ipynb
+++ b/g-h_filter.ipynb
@@ -1,7 +1,7 @@
 {
  "metadata": {
   "name": "",
-  "signature": "sha256:54842314075cdbcdc03bb78f35c3e8a836a4ff44b02d617f5738d57e43019ee4"
+  "signature": "sha256:2a864f60529fef582f39940035399ce8c5b054c28d9216e0503b36798631d661"
  },
  "nbformat": 3,
  "nbformat_minor": 0,
@@ -41,7 +41,7 @@
         "        margin-right: auto;\n",
         "    }\n",
         "    div.text_cell code {\n",
-        "        background: #FFFFFF;\n",
+        "        background: transparent;\n",
         "        color: #000000;\n",
         "        font-weight: 600;\n",
         "        font-size: 13pt;\n",
@@ -250,7 +250,7 @@
        "output_type": "pyout",
        "prompt_number": 1,
        "text": [
-        "<IPython.core.display.HTML at 0x1455c90>"
+        "<IPython.core.display.HTML at 0x7ff7604afd90>"
        ]
       }
      ],