Seems Janet Maslin got the jump on everyone with her review in the New York Times. She seems to consider it a dry but ultimately rewarding read, focusing almost exclusively on TR's wilderness legacy. Some time ago, I read The River of Doubt, which chronicles one of his last journeys on a tributary of the Amazon, later to be known as Rio Teodoro. It showed to what lengths TR would go for adventure, even when he was well past the age for such adventures. But, TR was always known as an advocate of The Strenuous Life. I was eventually able to find a book on Candido Rondon, Stringing Together a Nation, who was the actual leader of the ill-fated expedition, as it seemed that TR spent most of the time lying prostrate in a canoe.
Roosevelt was a big proponent of the Antiquities Act and used it to great effect from 1906 to the end of his term in 1908. Here is a brief history on the National Park Service filled with vintage photographs.