History continues to give up its secrets, and few ancient civilisations harbour secrets older or more extraordinary than that of ancient Egypt. Three years ago a donkey put its foot through a hole in the scorching sand near Bahariya Oasis, some 250 miles south-west of Cairo. What it revealed to the startled rider was a gilded arm. The archaeologists were quickly on the scene, and the find led to the discovery thus far of tombs containing over 100 mummies, many lavishly gilded, and dating from 1800 BC, when the Egyptian empire was at its most powerful, to the Greco-Roman periods. Generously illustrated, with an authoritative text by Dr Zahi Hawass - it should be since he has been in charge of the excavations - Valley of the Golden Mummies provides a comprehensive guide to one of the most significant finds of recent times. Who were the occupants of these tombs? How did they live? Some clearly were rich; others, wrapped untidily in linen, could never have afforded the shining armoury of wealth, the fine necklaces and amulets, all aimed at reaching the eternal afterlife. Cat scans and DNA tests will help prise open the secrets of Bahariya, but there may always be mysteries that elude science. Why, for example, did Dr Hawass suffer from nightmares in which he was haunted by children? He believes it was because he ordered mummies of two young children to be removed to a museum while leaving their father behind in the tomb. They were telling me they did not want to be separated, he writes. Fanciful rubbish? Dr Hawass, for one, doesn't think so..