David Allen, right, author of the bestselling book "Getting Things Done" takes part in a discussion with Guy Kawasaki, left, a Silicon Valley venture capitalist, at the first-ever Getting Things Done summit in San Francisco, Thursday, March 12, 2009. He may not be a household name, but in Silicon Valley, which worships at the altar of productivity, David Allen is a high priest. Since publishing his bestselling "Getting Things Done" in 2001, Allen has attracted legions of disciples to his gospel of stress-free personal efficiency.