Hardbound. We have now reached the mid-point of our editorial task of putting together the compendium, Principles of Medical Biology, which is supposed to be composed of twenty-five modules. The present single-volume module on reproductive endocrinology and biology is in more than one respect a continuation of Module 10 (in two volumes) dealing with molecular and cellular endocrinology. In addition, it intersects, as it should, with various parts of obstetrics and gynaecology, both of which are abetted by technology. One has only to recall that the practical benefits of ultrasound in perinatal medicine and in vitro fertilisation are the outcome of the technological revolution in biomedicine. Whether we are approaching a new era in reproductive biology following the invention of animal cloning is still hard to tell. For some people, it remains an article of faith that cloning of the human being is highly probable. For others, asexual reproduction is anathe