My top 3 are:
(1) "It Doesn't have to be Crazy at Work" by Jason Fried and David Hansson (of Basecamp)
(2) "Purple Cow" by Seth Godin
(3) "Blue Ocean Strategy" by W. Chan Kim? and Renée Mauborgne
Really a great question.
Selecting a favorite one is very tough for me. Because most of the time I read new books and they become my favorite. Some of them are: The Lean Startup, Start with Why, and Blackmart Alpha.
Emyth Revisited. A must read for any business owner. Good luck.
Good to Great by Jim Collins is an absolute must-read (or listen. I listened to it first, then bought hardcover copies of the book for all my team.) Get it and thank everyone that recommended it to you later. You'll see why when you get it - I guarantee. Contains many life and leadership lessons as well as business ones, and just utterly fascinating and rewarding to study. It's the book that keeps on giving!
For me, it has been several.
The first one for me has got to be Think and Grow Rich by Napoleon Hill. Although it was extremely confusing at first, it really got me to start thinking that I could start a business of my own.
My second favorite has got to be The E Myth by Michael Gerber. That book has been a real eye-opener! It made me understand why so many small businesses fail and what I need to do to build my home cleaning business to run like a well-oiled machine.
I keep a copy near my bed and I also have it on audio to listen to it in my car from time to time.
The Way of the SEAL by Mark Divine
When it comes to business, one has to be willing to embrace a warrior mindset and Divine's book really hit home for me. The focus on leading from the front and a mindset on offense translates well to business and in life. The former Navy SEAL commander has given me some great ideas and tools for the toolbox.
One good takeaway is to think offense all the time. This goes to how changing the words you use can change your attitude and your confidence.
A great book for those who want to dig deep and learn some great tactics.
Two of my favorites
Sell with a Story: How to Capture Attention, Build Trust, and Close the Sale: Book by Paul Smith
Blue Ocean Strategy - Book by Renée Mauborgne and W. Chan Kim