Lean Startup

• The Lean Startup by Eric Ries
• Lean Analytics - Ben Yoskovitz & Allistair Crowell
• UX for Lean Startups by Laura Klein
• Lean UX by Jeff Gothelf and Josh Seiden
• Running Lean by Ash Mauyra
• The Lean Entrepreneur by Brant Cooper and Patrick Vlaskovit
• Extreme Programming Explained by Kent Beck
• Business Model Generation: A Handbook for Visionaries, Game Changers, and Challengers by Alexander Osterwalder

Customer Development

• "The Four Steps to the Epiphany," by Steven Gary Blank
• "Four Steps" on CafePress is $10 cheaper
• "Crossing the Chasm,"  by Geoffrey Moore
• Especially Chapter 4 "Target The Point of Attack"
• "The Entrepreneur's Guide to Customer Development" by Brant Cooper and Patrick Vlaskovits
• e-book pdf here

Innovation

• "The Innovator's Dilemma," by Clayton M. Christensen
• "Achieving Planned Innovation" by Bacon and Butler

• "Only the Paranoid Survive: How to Exploit the Crisis Points That Challenge Every Company" by Andy Grove