Gribbin, that old warhorse of British science writing, here updates his 1982 book, The Monkey Puzzle with his co-author, Cherfas - tub-thumping across much of the same savannah. They highlight the work of Simon Easteal in particular, cheerleading the findings that we share 98.4% of our DNA with chimpanzees - and indeed that, although the chimp has 24 pairs of chromosomes, one human pair looks very like a joined-up version of two chimp-chromosome pairs. This, they assert, suggests that gorillas and chimps only parted company with man in the last 3.8 million years, and that differences may relate mostly to regulatory genes directing rates of development. Argumentative, convoluted and pass-remarkable, Gribbin and Cherfas are always entertaining, if not always 98.4% convincing.