My introduction to androgens was neither auspicious nor impressive. I was sitting my viva voce examination for a degree in physiology and had haltingly intimated to my examiner (name decorously withheld) that I intended to pursue a career in re- search. On what topic? was the reply. I had been deeply impressed by the work of C. Huggins and C. V. Hodges (Cancer Res. 1, 293, 1941) on the dramatic arrest of canine prostatic hyperplasia by the administration of stilboestrol. With some en- thusiasm, I responded, On steroid hormones, because I am struck by the profound effects that may be achieved by relatively small numbers of molecules. The examiner sank into deep contemplation before replying, Young man, have you considered go- ing into teaching? Suitably chastened, I finally began my research career investigating the effects of steroids on the nucleic acid metabolism of experimental tumours and on the process cells. Reaching an impasse in this work, I mentioned one of senescence in animal day to Dr. G. F. Marrian that, somewhat surprisingly, we had no understanding of the fundamental mechanism of action of steroid hormones, especially the androgens. me to tackle this problem, particularly since exciting new insights He encouraged were then being made into the interaction of radioactively labelled oestradiol-l? ,8 with such tissues as rat uterus.