Teddy Roosevelt died in 1919, just 10 years after leaving office, but he accomplished enough in that decade to justify the thickness of this final volume, the last in Edmund Morris’s trilogy about the man for whom “a strenuous life” defined both his creed and his schedule. The bare details are exhausting enough. Three weeks after attending the inauguration of William Howard Taft, his anointed successor, TR embarked on a year-long expedition in Africa. He and a teenaged son killed hundreds of large animals and sent some of their carcasses back to the Smithsonian, where, suitably stuffed, they continue to return tourists’ gaze.