23-year-old speleologist Michel Siffre made his investigation ""beyond time"" with a two months' survival experiment in the cold, damp solitude of the Scarasson Cavern (on the Franco-Italian frontier). The record is based on his diary, kept from the inception of the idea, through the preparations, descent, to the ascent. Time passed quickly but was often lost in the state of semi-hibernation that overcame him. It is interesting to see how the long night was spent (a little reading, music), what he ate (no vitamins or medicine), how he contended with fear (rockfalls, cave-ins) and the constants -- melting ice and seeping water. His hope is that he contributed something of value to space research. Absorbing and admirable.