Chapter 1, Controlling the Flow and Converting Types, talks about writing code that makes decisions, repeats a block of statements, and converts between types, and writing code defensively to handle errors when they inevitably occur. You will also learn the best places to look for help.
Chapter 2, Writing, Debugging, and Testing Functions, is about following the Don't Repeat Yourself (DRY) principle by writing reusable functions, and learning how to use debugging tools to track down and remove bugs, monitoring your code while it executes to diagnose problems, and rigorously testing your code to remove bugs and ensure stability and reliability before it gets deployed into production.
Chapter 3, Building Your Own Types ...
