Good Strategy/Bad Strategy

Steve Blank's blog (not a book, I know) + The Startup Owners Manual also by Steve Blank. Lean Product Playbook by Dan Olsen. The two helped me understand what it meant to 'get out of the building'. 7 Powers + Good Strategy Bad Strategy helped me think long term about the business model and evolution of the company.

I assume you're not interested in hearing the obvious ones (zero to one, lean startup, etc., etc.) so I'll recommend two. At the early stages when you're defining your strategy? "Good strategy/bad strategy" by Richard P. Rumelt. "Strategy" is thrown around a whole lot in business, often by somebody who is talking about a goal, as opposed to how to reach it. This book can get a little repetitive but the overarching teachings are valuable and will serve you well throughout your entrepreneurship journey. After the startup phase (growth/acquisition)? I recommend "The messy middle" by Scott Belsky.