Since the first observations of Busch in 1866, the possible use of heat as a therapeutic agent in the cure of cancer has been repeatedly subject to bursts of interest, almost invariably followed by periods of neglect and skepticism. In 1963-1964, this problem was again attacked by us both from the biochemical and from the clinical points of view. The first results of this joint effort were positive beyond expectation, and generated a new revial of studies aimed at the identification of the nature of the bio- chemical lesion as well as at the optimization of technique and of the therapeutic...