Son of man

Son of Man is a science fiction novel by American writer Robert Silverberg, published in 1971. The book is about Clay, a 20th-century man, who travels billions of years into the future and meets humanity in its future forms. Some of the issues discussed in the book are sexuality, telepathic communication between people, physical prowess or frailty, division of humans by caste or ability, and the preservation of ancient wisdom, among other things.