It was Thomas Henry Huxley, the master of the public forum, who set the agenda on the “monkey question.” In his little book Man's Place in Nature (1863), he argued that the anatomical similarities between humans and apes provide overwhelming evidence of our primate evolutionary origins. It is true that there are major differences between humans and the closest apes – the gorillas, the chimpanzees, and the orangutans – but the differences between us and them are less significant than are the differences between them and the lowest and most primitive monkeys.

There was some fossil evidence also. Thanks to the patient efforts of the Frenchman Boucher de Perthes, human origins were being pushed back in time, because our remains were being uncovered along with specimens of now-extinct organisms (Oakley 1964; Johanson and Edey 1981). Then, bones of an apparently primitive form of human were unearthed from the deposits in the Neanderthal region in Germany. Not that these were necessarily the much-desired and sought-for “missing link”: Huxley himself, for instance, decided that Neanderthal man was but a subspecies of Homo sapiens, rather than a new species in its own right. But the fossil discoveries did point in the right direction: a direction that was taken by the Dutch doctor Eugene Dubois at the end of the century when, in the East Indies, he discovered remains of the first unambiguously primitive humanlike (hominid) specimen (formerly “Java man,” Pithecanthropus, now assigned to Homo erectus).