This posthumous fragment of a book that Dr. Berlyne was writing at the time of his death was sent to MOTIVATION AND EMOTION by his colleagues at the University of Toronto. Its appearance in print is by permission of the Berlyne family and with appreciation to F. G. Hare and John Ogilvie of the University of Toronto and Seymour Weingarten of Plenum Publishing corporation, who were instrumental in providing a copy of the manuscript to the editor; to George Rappolt and Pat Monahan, of Clark University, who assisted in compiling the bibliography; and to Dr. Edward L. Walker, who provided some editing and wrote the brief introduction.
References to figures (in Chapters 1 and 3) were deleted, as no figures could be found to accompany the manuscript. In any case, it appeared that these would have merely supplemented the text and were neither new nor original, insofar as could be judged. The reader may further note that perhaps a half dozen references are missing, and others may not have been those intended by Dr. Berlyne.
While it seems unlikely that the chapters presented here were either complete or in their final draft stage, it was nevertheless felt that publication of even this fragment of Daniel Berlyne's last major work, with only minimal editing, would be of value to fellow students of motivation theory.
M.H.A.