TDD by example is a perfect book if you are looking for the first step into the TDD world.
I would say the book was divided into two main parts, the first one is how does the TDD works and how to do your own tests using a simple abstraction, by the way the problem presented was about currency. The second part is focus on creating your own TDD framework.
And here goes a tip for python developers, the second part of the book where Kent Beck give us a explanation of what is suit and how it works was entirely wrote in python. But the book is not wrote just using python is there a few sections were wrote in Java as well.
“Every programming practice encodes a value system, explicitly or implicitly. TDD is no different. If you’re happy slamming some code together that more or less works and never looking at the result again, TDD is not for you. TDD rests on a charmingly naïve geekoid assumption that if you write better code, you’ll be more successful. TDD helps you pay attention to the right issues at the right time so you can make your designs cleaner, you can refine your designs as you learn.”
Kent Beck, Test Driven Development By Example