Guess it is NOT a bestseller

[CapnCaveman]

Trying to remember a book. I thought it was a bestseller but after days of fruitless searching it may actually be suprisingly obscure.

Normal sized fictious novel. Contemporary. I believe it was written sometime in the 80s or 90s.

The plot alludes me, but the gist is that it is about a man who finds out about a secret race of people who have been living among us for centuries. They are some strange caveman offshoot that uses telepathy and dream sequences and other mental apparations to stay one with the tribe. They are primal. He discovers his wife is one and his son is a whole new species neither man nor whatever the cavemen are called (believe it is the title of the book).

My most vivid memory is that the man has a reoccurring dream he is lying naked on his back in a field of green with an erection in the sun. He is being neither shameful nor nasty, he is simply basking in his animal nature.

I believe it is a one word title that begins with M although the letter could be mistaken.