diff --git a/08_mfr/05_summary.ipynb b/08_mfr/05_summary.ipynb
new file mode 100644
index 0000000..361fbd0
--- /dev/null
+++ b/08_mfr/05_summary.ipynb
@@ -0,0 +1,75 @@
+{
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+  {
+   "cell_type": "markdown",
+   "metadata": {
+    "slideshow": {
+     "slide_type": "slide"
+    }
+   },
+   "source": [
+    "# Chapter 8: Map, Filter, & Reduce (TL;DR)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {
+    "slideshow": {
+     "slide_type": "skip"
+    }
+   },
+   "source": [
+    "The operations we do with sequential data commonly follow the **map-filter-reduce paradigm**: We apply the same transformation to all elements, filter some of them out, and calculate summary statistics from the remaining ones.\n",
+    "\n",
+    "An essential idea in this chapter is that, in many situations, we need *not* have all the data **materialized** in memory. Instead, **iterators** allow us to process sequential data on a one-by-one basis.\n",
+    "\n",
+    "Examples for iterators are the `map`, `filter`, and `generator` types."
+   ]
+  }
+ ],
+ "metadata": {
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+   "display_name": "Python 3",
+   "language": "python",
+   "name": "python3"
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+    "name": "ipython",
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+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython3",
+   "version": "3.8.6"
+  },
+  "livereveal": {
+   "auto_select": "code",
+   "auto_select_fragment": true,
+   "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"
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+}
diff --git a/CONTENTS.md b/CONTENTS.md
index 1309419..332a42f 100644
--- a/CONTENTS.md
+++ b/CONTENTS.md
@@ -226,4 +226,5 @@ If this is not possible,
     - [content <img height="12" style="display: inline-block" src="static/link/to_nb.png">](https://nbviewer.jupyter.org/github/webartifex/intro-to-python/blob/develop/08_mfr/04_content.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/08_mfr/04_content.ipynb)
       (Iterators vs. Iterables;
-       Example: `sorted()` vs. `reversed()`)
\ No newline at end of file
+       Example: `sorted()` vs. `reversed()`)
+    - [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/08_mfr/05_summary.ipynb)
\ No newline at end of file