At Winter's End by Robert Silverberg was originally published in 1988. My hardcover copy is 404 pages long. This story is continued in The New Springtime. Although I would recommend this to those who enjoy science fiction, I would have to say that I enjoyed the Majipoor Chronicles books by Silverberg more. My less-than-hardy recommendation could also be based on the fact that I generally prefer hard science fiction. At Winter's End was enjoyable, however, and I'll be reading The New Springtime next.
After a recurrence of the cataclysm that killed off the dinosaurs and a resulting Long Winter of 700,000 years, the eventual New Springtime sees only two of the far future Earth's original Six Peoples emerge from their deep cocoons: the resilient, insect-like hjjk-folk and the simian tribes who regard themselves as heirs to humanity. Young Hresh-full-of-questions is a member of one of the latter, a small band that must radically change its ancient rituals and taboos to adapt to their new life. Taking up temporary residence in the shell of a once great city, the group fearfully meets another people, is itself torn in half by rivalry and, through Hresh, achieves a new realization of who they are. This solid, dramatic novel expands on a favorite motif of Silverberg's: the mixed terrors and pleasures of freedom, of going out into the wider world without guide, map or a sure sense of one's own capabilities. Copyright 1988 Reed Business Information, Inc.
"It is possible that we are the only ones left anywhere, Torlyri thought. The idea was frightening. Just one fragile little band of some sixty men and women and children standing between humankind and extinction! Can we dare take any risk of destruction, she wondered, if we are the sole remnant of our kind?... It would be folly for the People to huddle in their cocoon until the end of time, waiting for absolute knowledge that it was finally safe to emerge. The gods never gave you absolute knowledge of anything. You had to take your chances and have faith."