In Y: The Descent of Men, the remarkable implications of an accident of biological evolution are brought to life by the award-winning science writer and British academic geneticist Steve Jones. Not to be confused with clothing sizes or brand names, the capital letters XX and XY refer to the approximate shapes of the sex determining chromosomes. Men have the smaller Y chromosome and confer gender differences on children through their sperm, a distinction that was only discovered in 1902. It was not so very long ago, as Jones reminds us, that scientists (male of course) thought that sperm carried a miniature human (homunculus) and a wife was "a mere seedbed; a step below (a husband) in society, in the household and, most of all, in herself". Since Darwin"s day, humans have been displaced from their place just below the angels in the grand scheme of life. And now to further our ignominy and descent, within the human genome, the male Y chromosome is, as Jones puts it, "the most decayed, redundant and parasitic of the lot". Furthermore, man himself may become redundant, for his sperm can be grown in animal testes, and in mice at least an egg can be fertilised with a body cell from another female. Steve Jones is a brilliant science writer, capable of teasing, cajoling, entertaining and educating the reader without pain. Jones has not only pinched Darwin"s title The Descent of Man but learned his technique of persuasion in which the potential critic is disarmed by having the faults, problems and dirt on the subject brought out into the open and given a good public washing. So with men and masculinity, as Jones details with telling detail and great humour, our biological inheritance and its social implications have left an immense wake of problems which will need to be sorted if men and humanity are to get over the crisis of modern manhood. So come on now chaps, pull yourselves together, dump the techie toys and mags and check out why your organ is so dangerous and what to do about the problem. For a first step, give yourself a treat, read this book and allow yourselves to be entertained and informed, if not necessarily reassured. --Douglas Palmer.