Time's Last Gift

Essef - It was a timeship, with three men and a woman on board. Without moving a micron in space, it had traveled from 2070 A.D. to 12,000 B.C. - a journey that could never be repeated. For the three men and the woman, all anthropologists, it was once-in-a-million-lifetimes expedition... a chance to study primitive man as modern man never could...