It is curious that research in endocrinology has largely ignored the testis until quite recently. There were two impor tant reasons for this neglect; first, methods of study were difficult, and second, sperinatogenesis was considered to be the concern of the urologist or cell biologist but not the endocrinologist. Since it is now almost an ethical imperative that we develop a male contraceptive, and since a host of new techniques can be brought to bear on problems of testis function, research in male reproductive biology has effloresced. In fact, it has become possible to project aseries of workshops on the testis, each dealing with discrete aspects of biochemistry, physiology and pathology. It is fitting that this first Workshop should be on Binding and Activation, since this area is one of the frontiers in endocrinol ogy. At our present rate of progress it is probable that each of the succeeding workshops will likewise bring together leaders in a rapidly developing area. The National Institute of Child Health and Human Development has the major Federal respon sibility in reproductive biology, and has therefore agreed to sponsor this and succeeding workshops. On behalf of the Institute and for those members of the Committee who have organized this meeting, I welcome you. I am quite sure that this first Workshop on the Testis will initiate aseries of important contributions to scientific thought in male reproduc tive biology. Mortimer B. Lipsett, M. D.