Mike Michalowicz
Clockwork
I see so many owners stuck doing every task themselves. They make every decision, answer every question, and when someone leaves, there's nothing written down to train the next person. Clockwork explains why that happens and how to get out of it: shift from doing the work to designing how the work gets done.
The idea I love most is the four-week vacation. Plan it, commit to it, and then build the systems that make it possible. If your business can run without you for four weeks, you haven't just bought yourself a vacation. You've built something stable, something you can grow, and something you can actually enjoy.