The Beast is a novel written by Walter J. Sheldon. It was first published in 1980.
There had been sightings before, but this was proof - a giant molar taken from a huge skeleton decaying high in the Northwest wilderness. It wasn't as much evidence as anthropologist Zia Marlowe wanted, but it was enough to get financing for an expedition - one that could prove once and for all that Bigfoot did exist.
But for Joe McBay, whose late buddy had found the tooth; Dick Charterhouse, whose corporation was backing the trek; and Zia, the expedition would prove to be much more revealing. For the beast they sought not only lived, it thought - and it had been thinking about a confrontation with man for a long, long time...