diff --git a/07_sequences/06_summary.ipynb b/07_sequences/06_summary.ipynb
new file mode 100644
index 0000000..8115139
--- /dev/null
+++ b/07_sequences/06_summary.ipynb
@@ -0,0 +1,85 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {
+    "slideshow": {
+     "slide_type": "slide"
+    }
+   },
+   "source": [
+    "# Chapter 7: Sequential Data (TL;DR)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {
+    "slideshow": {
+     "slide_type": "skip"
+    }
+   },
+   "source": [
+    "**Sequences** are an *abstract* concept that summarizes *four* behaviors an object may or may not exhibit. Sequences are\n",
+    "- **finite** and\n",
+    "- **ordered**\n",
+    "- **containers** that we may\n",
+    "- **loop over**.\n",
+    "\n",
+    "Examples are the `list`, `tuple`, but also the `str` types.\n",
+    "\n",
+    "Objects that exhibit all behaviors *except* being ordered are referred to as **collections**.\n",
+    "\n",
+    "The objects inside a sequence are called its **elements** and may be labeled with a unique **index**, an `int` object in the range $0 \\leq \\text{index} < \\lvert \\text{sequence} \\rvert$.\n",
+    "\n",
+    "`list` objects are **mutable**. That means we can change the references to the other objects it contains, and, in particular, re-assign them.\n",
+    "\n",
+    "On the contrary, `tuple` objects are like **immutable** lists: We can use them in place of any `list` object as long as we do *not* need to mutate it. Often, `tuple` objects are also used to model **records** of related **fields**."
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 3",
+   "language": "python",
+   "name": "python3"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 3
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython3",
+   "version": "3.8.6"
+  },
+  "livereveal": {
+   "auto_select": "code",
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+   "scroll": true,
+   "theme": "serif"
+  },
+  "toc": {
+   "base_numbering": 1,
+   "nav_menu": {},
+   "number_sections": false,
+   "sideBar": true,
+   "skip_h1_title": true,
+   "title_cell": "Table of Contents",
+   "title_sidebar": "Contents",
+   "toc_cell": false,
+   "toc_position": {
+    "height": "calc(100% - 180px)",
+    "left": "10px",
+    "top": "150px",
+    "width": "384px"
+   },
+   "toc_section_display": false,
+   "toc_window_display": false
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 4
+}
diff --git a/CONTENTS.md b/CONTENTS.md
index bb9df6c..ac2e795 100644
--- a/CONTENTS.md
+++ b/CONTENTS.md
@@ -186,4 +186,5 @@ If this is not possible,
       (Packing & Unpacking with Functions)
     - [appendix <img height="12" style="display: inline-block" src="static/link/to_nb.png">](https://nbviewer.jupyter.org/github/webartifex/intro-to-python/blob/develop/07_sequences/05_appendix.ipynb)
       [<img height="12" style="display: inline-block" src="static/link/to_mb.png">](https://mybinder.org/v2/gh/webartifex/intro-to-python/develop?urlpath=lab/tree/07_sequences/05_appendix.ipynb)
-      (`namedtuple` Type)
\ No newline at end of file
+      (`namedtuple` Type)
+    - [summary <img height="12" style="display: inline-block" src="static/link/to_nb.png">](https://nbviewer.jupyter.org/github/webartifex/intro-to-python/blob/develop/07_sequences/06_summary.ipynb)
\ No newline at end of file