The 4-Hour Workweek
I’ve read HUNDREDS of books, but this book is one of only 2-3 I’ve read cover to cover more than once. It changed my view on lifestyle design, caused me to think critically about risk and led to many, many productive experiments. If you haven’t read it, DO. If you have, consider reading again.
Note: there are a few parts that may not be applicable to you, so use it as a textbook (meaning highlight things that matter for continued reference and thought, but skim and ignore parts that aren’t as relevant).