Whole great chunks of written history are of little value to the psychohistorian, while other vast areas which have been much neglected by historians — childhood history, content analysis of historical imagery, and so on — suddenly expand from the periphery to the center of the psychohistorian's conceptual world, simply because his or her own new questions require material nowhere to be found in history books.

Ch. 2 - Foundations of Psychohistory (1982)