Beginner's mind is an introductory concept of Zen Buddhism. The canonical story is that of the empty cup: if you hold on tightly to what your cup is filled with, your cup will never have room for new knowledge. See Shunryu Suzuki's Zen Mind, Beginner's Mind (Weatherhil, 1972).
 From James R. Chiles, Inviting Disaster: Lessons from the Edge of Technology (HarperBusiness, 2002).
 A good summary of matrix and other organization types can be found in Steven A. Silbiger's The Ten-Day MBA (William Morrow and Company, 1993), pp. 139-145. But almost any book on management theory covers this topic.
 Once, while dining at the Pizzeria Uno in Pittsburgh, my friends and I were told a table would be ready in 10 minutes. Exactly 10 minutes later, my friend Chad McDaniel asked about our table. The hostess told us it would be ready in 10 minutes. Chad asked, "Is this the same 10 minutes or a different 10 minutes?" She didn't appreciate the joke.
 You can find a good comparative discussion of traditional and agile methods for software development in ...