diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..0b84df0
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+*.html
\ No newline at end of file
diff --git a/collaborators.sh b/collaborators.sh
new file mode 100644
index 0000000..9b3a275
--- /dev/null
+++ b/collaborators.sh
@@ -0,0 +1,27 @@
+#!/bin/bash
+
+collaborators=( "lawrancej" "UnZinkable" "mrpenguin7" "CyDrive" "jcamps" "powersa2" "AllTheAction" "lapatink" "tannerd01" "kirip" "tomleo" "garciaa1" "KBVuong1" "RoboCafaz" "LynxStar" "theCompanyDream" "aghon" "SoxMax" "nhogan11" "finna" "CyaSteve" "sthdips09" "torosianj" "vafaeed" "cantrellk" "dalswaimil" )
+
+if [ $# = 0 ]; then
+	echo "Do git commands for all collaborators."
+	echo ""
+	echo "Usage:      $0 COMMAND"
+	echo ""
+	echo "Where COMMAND is one the following:"
+	echo "setup       Do git remote add for all collaborators"
+	echo "fetch       Do git fetch for all collaborators"
+	echo "clean       Do git remote rm for all collaborators"
+	echo ""
+	echo "Example: $0 setup"
+elif [ $1 = "fetch" ]; then
+	git fetch --all
+else
+	for collaborator in "${collaborators[@]}"
+	do
+		if [ $1 = "setup" ]; then
+			git remote add $collaborator https://github.com/$collaborator/CompilerDesign.git
+		elif [ $1 = "clean" ]; then
+			git remote rm $collaborator
+		fi
+	done
+fi
diff --git a/git.md b/git.md
index c8e06e8..d5bb0fe 100644
--- a/git.md
+++ b/git.md
@@ -52,15 +52,23 @@ Using git
 ---------
 Typically your use of git will involve (assuming you're on your master branch):
 
-Make a change to `some_file`
+### How do I know what I changed?
 
-    git add some_file
+    git diff # This will show changes that you've made.
 
-Make a change to `another_file`
+### How do I create a new branch?
 
-    git add another_file
+    git checkout -b some_new_branch
 
-What did I do?
+### How do I add a new file to git?
+
+    git add new_file
+
+### How do I add all changes I've made to the current commit?
+
+    git commit -a -m "Message goes here"
+
+### What did I do?
 
     git status    # Show the status of the index, staging area, and untracked files
     gitk --all &  # Show a graphical timeline of commits
diff --git a/index.md b/index.md
index e6b72f4..536a0e9 100644
--- a/index.md
+++ b/index.md
@@ -14,6 +14,11 @@ Examples:
 - GCC, Clang, Visual C++ translate C into machine code
 - LaTeX, Pandoc translate document markup into PDF, HTML, etc.
 
+Follow-up:
+
+- [How do compilers work](#what-are-the-phases-of-a-compiler)?
+- [Who developed the first compiler](#who-is-grace-hopper)?
+
 ### What is a language?
 A [set](background.md#what-is-a-set) of [strings](background.md#what-is-a-string).
 
@@ -26,14 +31,50 @@ Examples and counterexamples:
 ### What is Chomsky's hierarchy?
 
 ### What is an interpreter?
+An interpreter is a type of compiler that simply executes the code directly without translating it to a lower level.
+
+Examples:
+
+- Debuggers
+- Scripting languages
+
+Follow-up:
+
+- [How do interpreters work](#how-do-interpreters-work)?
 
 ### The C compiler is written in C. How can that be?
 
 ### What are the phases of a compiler?
-List the phases here. Briefly describe what each phase does. Give examples.
+Compilers operate around these phases:
+
+Front end (process source language):
+
+- [Scanner (Lexical analyzer)](#what-is-a-scanner). Split source code (a [string](background.md#what-is-a-string)) into a token sequence.
+- [Parser (Syntactic analyzer)](#what-is-a-parser). Check if token sequence conforms to language grammar and construct the [parse tree](#what-is-a-parse-tree) or [abstract syntax tree](#what-is-an-abstract-syntax-tree).
+- [Type checker (Semantic analyzer)](#what-is-a-type-checker). Check if the program is [semantically valid](#what-is-semantics).
+
+Middle end (an intermediate representation):
+- [Translator](#what-is-a-translator). Convert an abstract syntax tree into an [intermediate representation](#what-are-intermediate-representations).
+- [Optimizer](#what-is-optimization). Improves IR code by eliminating redundancy and [dead code](#what-is-dead-code).
+
+Back end (generate target language):
+- [Code generator](#what-is-code-generation). Produces machine code.
 
-### Who is Grace Hopper?
+### How do interpreters work?
+Interpreters consist of the exact [same phases of a compiler](#what-are-the-phases-of-a-compiler), but execute programs instead of [generating machine code](#what-is-code-generation).
 
+### Who is [Grace Hopper](http://www.smbc-comics.com/?id=2516)?
+
+#### Military Career
+
+#### Contributions to Computer Science
+ - Developed the first compiler for a computer programming language.
+ - Conceptualized machine-independent programming languages.
+ - Popularized the term "debugging."
+ 
+#### Honors
+ - "Computer Sciences Man of the Year" award from the Data Processing Management Association in 1969
+ 
 Regular languages
 -----------------
 
@@ -108,6 +149,22 @@ Abstract Syntax Trees
 
 ### What is the visitor design pattern?
 
+Semantics
+---------
+### What is semantics?
+
+### What is static semantics?
+
+### What is runtime semantics?
+
+### What is type-checking?
+
+Intermediate representations
+----------------------------
+### What are intermediate representations?
+
+### What is a translator?
+
 Optimization
 ------------
 ### What is optimization?
@@ -122,6 +179,8 @@ Optimization
 
 ### What is method inlining?
 
+### What is dead code?
+
 Code generation
 ---------------
 ### What is code generation?