An expert distillation of the course of biological learning as it grew from Grecian times to the present, discloses the highlights of scientific progress as man came to know more and more of the life around him. Following Aristotle's work as the ""first biologist"", Pliny emerges in Roman times as an assiduous compiler of extant knowledge. Though it suffered a setback in the middle ages, zoological learning was kept alive by the herb gatherers who cured with their findings, and if much of the famous Physiologus was based on superstition it sustained an interest in natural surroundings. Vesalius and Harvey were the first whose powers of observation started zoology on its way towards the accumulation of factual knowledge that is ours today. Further impetus came with the invention of the microscope, with Linneaus' comprehensive system of classification, with the determination of evolution by Darwin, and with Mendel's theory. A fruitful interweaving of fact and historical detail connects main trends with many sidelights to produce a readable, compact survey.