There was a time, not all that long ago, when scientific study of the cell was called cytology, and the workers in the field named themselves cytologists. When I was a medical student, lectures in cytology were a special, segregated part of the curriculum in the histology course, given along with general anatomy, and they were, as I recall, the surest of cures for insomnia. I still possess Cowdry's three-volume set entitled Special Cytology, published in 1934, and leafing through these books today is rather like examining a medieval manuscript. You could never have guessed what was going to happen to the field. At that time it was all structure, and all guesswork about the structure. When cells were packed together in various tissues, how did the geometry of packing work? How many sides did a liver cell have, in real life? What on earth were all those granules in­ side, and what were the best stains for looking at them? One thing about those granules, they never moved. Indeed, nothing moved. Cytology turned into cell biology much later on, and suddenly came alive. As has been the case in so many diSciplines in biology, it was brought to life by techniques. New instruments and cytochemical methods were devised for look­ ing at cells, manipulating cells, more or less in vivo.