On September 23, 1926, and Austrian experimental biologist named Dr. Paul Kammerer blew his brains out on a footpath in the Austrian mountains. His suicide was the climax of a great evolutionary controversy which his experiments had aroused. The battle was between the followers of Lamarck, who maintained that acquired characteristics could be inherited, and the neo-Darwinists, who upheld the theory of chance mutations preserved by natural selection. Dr. Kammerer's experiments with various amphibians, including salamanders and the midwife toad (Alytes obstetricans), lent much weight to the Lamarckian argument and drew upon him the full fury of the orthodox neo-Darwinists. Arthur Koestler had known about Dr. Kammerer's work when he himself was a student in Vienna, and he has always been interested in this tragic story. He gives a fascinating description of the venomous atmosphere in which the battle was fought and of the lengths to which apparently respectable scholars would go to discredit their opponents. Heading the attack on Kammerer was a British scientist, William Bateson, who hinted that the Viennese's experiments were fakes, but who failed to examine the evidence, including the so-called nuptial pads of Kammerer's last remaining specimen of the midwife toad. It was a young American scientist who delivered the coup de grace; on a visit to Vienna, he discovered that the discoloration of the nuptial pads was due not to natural causes but to the injection Indian ink. When his findings were published, Kammerer shot himself. Mr. Koestler, whose recent writings, in books such as The Act of Creation and The Ghost in the Machine, have been in part concerned with evolutionary theory, decided to investigate this old mystery. When he started on his researches, he expected to relate the tragedy of a man who had betrayed his calling, for Kammerer's suicide was accepted as a confession of guilt and his work was discredited from that day to this. Instead, as Mr. Koestler read the contemporary papers, corresponded with Kammerer's daughter, Bateson's son, and the surviving scientists who attended Kammerer's lecture in Cambridge, he found himself writing a vindication of a man who in all probability was himself betrayed. The story that emerges is, on one level, fascinating piece of scientific detection; on another, it is a moving and human narrative about a much abused, brilliant and lovable figure. Though no Lamarckian himself, Mr. Koestler ends the book with an appeal to biologists to repeat Kammerer's experiments with an open mind in order to verify or refute them. If Kammerer's claims were posthumously confirmed our outlook on evolution would be significantly changed. A superb intellectual thriller whose implications still reverberate today, The Case of the Midwife Toad is an entirely new kind of book for Mr. Koestler, and perhaps only he could have written it, for it required expert knowledge and familiarity with the academic world of science, combined with the creativity and imaginative insight of an outstanding novelist.

In The Sleepwalkers and The Act of Creation Arthur Koestler provided pioneering studies of scientific discovery and artistic inspiration, the twin pinnacles of human achievement. The Ghost in the Machine looks at the dark side of the coin: our terrible urge to self-destruction... Could the human species be a gigantic evolutionary mistake? To answer that startling question Koestler examines how experts on evolution and psychology all too often write about people with an 'antiquated slot-machine model based on the naively mechanistic world-view of the nineteenth century. His brilliant polemic helped to instigate a major revolution in the life sciences, yet its 'glimpses of an alternative world-view' form only the background to an even more challenging analysis of the human predicament. Perhaps, he suggests, we are a species in which ancient and recent brain structures - or reason and emotion - are not fully co-ordinated. Such in-built deficiencies may explain the paranoia, violence and insanity that are central strands of human history. And however disturbing we find such issues, Koestler contends, it is only when we face our limitations head-on that we can hope to find a remedy.

The most adventourous, polymathic - and readable - scientific populariser of the age offers in Janus a summing up of a quarter of a century's study and speculations on the life sciences and their philosophic implications. Koestler has an interesting theme to propose. It is this; the human brain has developed a terrible biological flaw, such that it is working now against the survival of the race. Something has "snapped" inside the brain. It is no longer necessarily a function which will lead us to a better world, but something demonic, possessed, perhaps even evil. The anguished humanity of Koestler's concepts and the lucid energy of his style comman respect. Here is one of the major political "experiencers" an dmost widely informed spirits of the age turning to the crux of human survival on a ravaged planet. The title of the book tells not only of a central allegory of division in the human species. It stands for the rare tension on Koestler's discourses: between desolation and zest, between darkness and noon.