Told in the first-person narrative of Paul Loyd, divorced owner of a small town restaurant, Ancient of Days tells the story of a habiline man found wandering in a Georgia pecan orchard, a living descendant of a habiline tribe brought from Africa via Haiti as a slave.  Paul's ex-wife, Ruth-Claire, takes in the living fossil, appropriately naming him Adam, and as an artist she discovers Adam's mute but vibrant artistic sensibility, falls in love with him, and marries him -- much to Paul's confusion and dismay.
[From the flyleaf of the Arbor House edition]

Dedication:
For David Hartwell, who has ridden to the rescue more times than the U. S. cavalry.