""The Four Phyla of Oligocene Titanotheres"" is a scientific book written by Henry Fairfield Osborn and published in 1902. The book focuses on the classification and study of extinct species of mammals known as titanotheres, which lived during the Oligocene epoch, approximately 34 to 23 million years ago. Osborn divides the titanotheres into four distinct groups or phyla based on their anatomical features and evolutionary relationships. He provides...