The death of Sir Henry Hallett Dale two years ago brought to a close an era which was characterized by tremendous pharmacologic advancements. During this period, the employment of what present investigators might consider "primitive" techniques yielded information which has become classic. For example, in a paper by Barger and Dale, published in 1910*, one finds not only a beautiful example of a structure-activity study and suggestions of the importance of membranes, but also the concept of specific receptor sites introduced by the statement that "the relation of the receptive mechanism to the base (i. e. , drug base) may well be one of solid solution of adsorption, and, therefore, more analogous to that of an enzyme to its substrate . . . " The search for drug receptors continues today at an accelerated pace. Hopefully, fundamental knowledge of receptors and the nature of drug-receptor interactions will lead to a rational approach to drug design. In acquiring skills in the scientificapproach to drug mechanism and evaluation, the modern pharmacologist, whether senior investigator or student, frequently is required to employ techniques which are characteristic of other biologic areas. However, it is not enough simply to be grounded in physiology or biochemistry.