Here are some books recommended by members of the Balanced Team Group. They cross a variety of disciplines and methodologies. Think something should be added? Let us know in the comments!
User-Centered Agile Method
by Hugh Beyer
Four Steps to the Epiphany
by Steven Gary Blank
The Entrepreneur’s Guide to Customer Development
by Brant Cooper & Patrick Vlaskovits
The Back of the Napkin
by Dan Roam
101 Things I Learned In Architecture School
by Matthew Frederick
Agile Software Development with Scrum
by Ken Schwaber & Mike Beedle
The book that formalized Scrum.
by David Andersan