Allen Holub is an author, consultant and trainer specializing in agile process and architecture (designing for volatility). He helps companies achieve true agility (as compared to learning some process by rote) at all levels from executive coaching to programmer training, focusing on designing for an Agile environment and on non-tribal agile processes.
He teaches in-house classes, gives public classes though his company (http://holub.com), and teaches for the University of California Extension. He's written a dozen books and hundreds of magazine and blog articles. He was a Contributing Editor for Dr. Dobb's Journal and JavaWorld, a former columnist for SD Times (Java Watch), and has written the OO Design Process column for IBM DeveloperWorks. He has also written for Microsoft Systems Journal, Programmers Journal, BYTE Magazine, Windows Tech Journal, Mac Tech Journal, C Gazette, and others