A young speleologist, twenty-three, Michel Siffre made his investigation ""beyond time"" with a two months survival experiment in a hostile environment, in the solitude, darkness, cold and above all dampness of a cave, the glacier in the Scarasson Cavern (on the France-Italian frontier). This record is based on the diary he kept from the inception of the idea, to the preparation, and finally the descent to the subterranean vault of ice where the telephone (outgoing only) was his only contact with the world above. Time passed quickly, often it was lost, in the condition of torpor or ""hypothermia"" (a semi-hibernation) which overtook him; memory was blurred; there were fitful depressions; but it is interesting to see how the long night was spent (a little reading, music), what he ate (no vitamins or medicines), how he contended with fear (cave-ins, rockfalls) and the constants- melting and seeping water. Finally the ascent and what was established and contributed, of particular value he hopes for future space research. Except for the occasional declamatory remark (French perhaps- or youthful), this account of physical stress carried to the farthest point of human endurance is not only absorbing but, after all, pretty admirable.