A great book
"The Tree Where Man Was Born" is, indeed, excellent, one of Matthiessen's best. He has a great knack for communicating extraordinary journeys without being sensationalistic about them. It's hard to imagine a book about a white westerner wandering through Africa being published these days without trumpeting jacket cover hubris ("chilling adventures with savage wildlife in Africa's bush country!").
"Blue Meridian: The Search for the Great White Shark" is also a fine book and, though it sounds like a boy's adventure story, it too is much more, as we have come to expect of his works.