Lean Startup

• The Lean Startup by Eric Ries
• Lean Analytics by Ben Yoskovitz and Allistair Croll
• Lean B2B by Etienne Garbugli 
• UX for Lean Startups by Laura Klein
• Lean UX by Jeff Gothelf and Josh Seiden
• Running Lean by Ash Maurya
• The Lean Entrepreneur by Brant Cooper and Patrick Vlaskovit
• Extreme Programming Explained by Kent Beck and Cynthia Andres
• Business Model Generation: A Handbook for Visionaries, Game Changers, and Challengers by Alexander Osterwalder and Yves Pigneur

Customer Development

• "The Four Steps to the Epiphany" by Steve Blank
• "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
• Lean Customer Development by Cindy Alvarez

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

Project Management

• Agile Project Management by Ken Schwaber

Lean Startup for Big Companies

• The Lean Enterprise by Trevor Owens and Obie Fernandez