The backwoodsmen, he says, "all tilled their own clearings, guiding the plow among the charred stumps left when the trees were chopped down and the land burned over, and they were all, as a matter of course, hunters. With Boon, hunting and exploration were passions, and the lonely life of the wilderness, with its bold, wild freedom, the only existence for which he really cared. He was a tall, spare, sinewy man, with eyes like an eagle's, and muscles that never tired; the toil and hardship of his life made no impress on his iron frame, unhurt by intemperance of any kind, and he lived for eighty-six years, a backwoods hunter to the end of his days. His thoughtful, quiet, pleasant face, so often portrayed, is familiar to every one; it was the face of a man who never blustered or bullied, who would neither inflict nor suffer any wrong, and who had a limitless fund of fortitude, endurance, and indomitable resolution upon which to draw when fortune proved adverse. His self-command and patience, his daring, restless love of adventure, and, in time of danger, his absolute trust in his own powers and resources, all combined to render him peculiarly fitted to follow the career of which he was so fond."* * Winning of the West, 1, 137, 138 (ed. 1889). Roosevelt contributed two volumes to the American Statesmen Series, one on Thomas Hart Benton in 1886, and the other on Gouverneur Morris in 1887. The environment and careers of these two men--the Missouri Senator of the first half of the nineteenth century, and the New York financier of the last half of the eighteenth--afforded him scope for treating two very diverse subjects. He was himself rooted in the old New York soil and he had come, through his life in the West, to divine the conditions of Benton's days. Once again, many years later (1900) he tried his hand at biography, taking Oliver Cromwell for his hero, and making a summary, impressionistic sketch of him. Besides the interest this biography has for students of Cromwell, it has also interest for students of Roosevelt, for it is a specimen of the sort of by-products he threw off in moments of relaxation. More characteristic than such excursions into history and biography, however, are his many books describing ranch-life and hunting. In the former, he gives you truthful descriptions of the men of the West as he saw them, and in the latter he recounts his adventures with elk and buffalo, wolves and bears. The mere trailing and killing of these creatures do not satisfy him. He studies with equal zest their haunts and their habits. The naturalist in him, which we recognized in his youth, found this vent in his maturity. And long years afterward, on his expeditions to Africa and to Brazil he dealt even more exuberantly with the natural history of the countries which he visited.