The final chapter of my book on Behavior Therapy (Yates, 1970) was completed in December 1968, and it was published almost exactly one year later, the review of the literature being reasonably complete up to about October 1968. In the preface I pointed out that work on the book had occupied me from 1964 to 1968 but that the initially slow progress turned out to be a blessing in disguise because of the enormous acceleration in publications in this area which took place after 1966. I pointed out that probably about 300 publications a year, not including books, were appearing on behaviour therapy by 1968.T h e term "SD(1)" will be used to refer to therapy where the feared objects (situations, etc.) are imagined by the subject; the term SD(R) will be used where the feared objects, etc., themselves are presented.