Eric Ries is the author of the popular blog Startup Lessons Learned and the creator of the Lean Startup methodology. He co-founded and served as CTO of IMVU, his third startup, which has today has over 40 million users and 2009 revenue over $22 million. An entrepreneur in residence at Harvard Business School and a frequent speaker at business events, he advises startups on business and product strategy using the Lean Startup approach.

Here is a collection of some of content on what he preaches:

RailsConf 2011: Eric Ries, "Lessons Learned"

Seattle GTUG - The Lean Startup

Entrepreneurial Thought Leader Lecture Series

Testing Your Assumptions