Front cover of a first edition.
Time and Again is a 1951 science-fiction novel by Clifford D. Simak.
Plot[]
Asher Sutton discovers he is destined to write a book that will help androids become more human, a book that would make humans equal with all creatures, rather than towering above them. However Sutton is the target of many groups who want to influence or prevent the book from being written.
He is helped by two beings, an android and Eva, an android masquerading as a human. The reason for Eva doing this is to trick Sutton into thinking that there are still humans who belive in the message his book will give. At the end of the novel, Sutton leaves for a distant planet to write his book.