This is the first time that the title Comparative Pharmacology appears within the covers of the Annual Review of Pharmacology, The Annual Review of Physiology has made it a practice, since 1951, to include each year a section on Comparative Physiology. It is well to pause and to examine the needs and meaning of the prefix "comparative. " In the Introduction to his important text on comparative physiology, August Puetter (1) wrote in 1911,The knowledge of scientifi c laws, as sought by physiology, is reached by a process of abstraction of the common from the abundance of single phenomena. The activity which leads to the cognition of the common (general), is that of comparing and so every scientific work in the field of physiology and every work which transgresses the pure empirical establishing of single facts, is an effort in the sense of " comparative" Physiology. The comparing is the most essential method which we use in science. Does it, under these circumstances, make any sense at all to speak of "Comparative Physiology?" Are not .. . physiology and comparative physiology the same?In the famous eleventh edition of the Encyclopedia Britannica, Ralph Stockman (2) investigates the scope of pharmacology in various countries and comes to the conclusion that,In English speaking countries and [with] the majority of German writers, [pharma cology is] the study of the action of chemical substances (as apart from foods) on all kinds of animals, from bacteria up to man; it is, in fact, a comparative study of the action of chemical bodies on invertebrate and vertebrate animals.