This book stems from the belief that undergraduate, and many graduate, students in geomorphology are taught far too little about the theoretical foundation of the discipline. This is a tragic oversight because all disci­ plines exist solely by virtue of a body of theory; furthermore, all substan­ tive research must, of necessity, be directed at improving this body of theory. While the centrality of theory is a characteristic of all science, it appears that it is fieldwork that has achieved sacrosanct status in geo­ morphology. The supreme standing of fieldwork would seem at first sight to be supported by such comments as that cited by Ager (1984, p. 42): "My old professor - the great H. H. Read - once said, 'The best geologist is, other things being equal, he who has seen the most rocks'. " The key issue in Read's comment is obviously "other things being equal"; what are these other things? For they will be just as applicable to geomorphology as to geology at large. One is certainly personal ability, but another critical com­ ponent is the individual's knowledge of relevant theory. Pursuit of theo­ retical knowledge is not generally a favored activity in geomorphology, a situation epitomized by Chorley's (1978, p. 1) one-liner: "Whenever anyone mentions theory to a geomorphologist, he instinctively reaches for his soil auger.