In the justly famous opening speech of Shakespeare’s Henry V, Chorus confronts the audience with several rhetorical questions: “Can this cockpit hold the vasty fields of France? Or may we cram within this wooden O, the very casques that did affright the air at Agincourt?” Probably not, but we might come close if we exercise our imaginations! As editor of this encyclopedia, I have been faced with a parallel set of questions: Can I cram within these two handsome volumes an account of every theory and philosophical position that has been put forward in the realm of education? And can the accounts that do get included be concise, scholarly, and readable? The answer to the first of these is “certainly not,” but the answer to the second, I am confident, is “yes.”