The output of the human genome project is a heavy duty subject – just understanding what’s involved in the process is not easy; interpreting the results operates at a wholedifferent level. As for writing about the human genome in an accessible and enjoyable way – this is a particularly drastic challenge. Ridley not only succeeds but does so in a rather cute fashion. This is ‘an autobiography of a species in 23 chapters’. The number 23 is no random selection – it corresponds to the number of chromosome pairs we have, and Ridley picks out a gene to feature from each chromosome pair in each chapter. This approach enables his book to be far reaching, looking at our relationship to other owners of the gene, from bacteria to great apes, spanning from the earliest forms of life to the genes that could be responsible for intelligence and language. Evolutionary theory, biology’s great triumph, is put across very effectively alongside good background material on genetics, and of the man