If you know Charles Siebert's earlier work -- his New York Times magazine pieces about elephants and whales, or his novel, "Angus," told from the point of view of a dying dog -- you know how fascinated he is by the link between animals and humans. He clearly believes that animals have a much higher level of awareness than most people give them credit for, yet he never crosses the line into anthropomorphizing. (Tricky enough, when you're trying to tell a story from a dog's point of view.)

His new book, "The Wauchula Woods Accord: Toward a New Understanding of Animals," is about that link, this time through an examination of great apes. Siebert travels the country, visiting animal sanctuaries for chimps who have retired -- or, more often, have been discarded -- from circuses and television work. When he gets to Wauchula, Fla., and sees a chimp named Roger, there is instant recognition -- on the part of the chimp. It is unmistakable, "as though he'd somehow been expecting me all along," Siebert writes.

The spine of this story is one night with Roger, Siebert sitting outside the cage, trying to understand the strong connection between them. As he sits, he thinks back to other chimps he has encountered in his research, the broader relationship between humans and animals, the inclination to humanize these animals, and the damage that causes. And he tries to figure out whether it is possible that Roger really did recognize him, whether they have met somewhere before.

It's a fine line that Siebert walks, not sentimentalizing animals, but also not relegating them to the "them" position of an "us and them" world. In the end, he concludes, we are all interconnected, all part of a continuum, and the way we treat animals ultimately reflects the way we treat each other, and the world.

LAURIE HERTZEL