Thelen describes his early education and decision to choose chemistry over law; his discovery that "personal ability is 85% generalized and only 15% specialized" and how that led him into numerous non-scientific undertakings such as union organizing; his first job with Certain-Teed Products which led to his interest in rheology, his initial experiments in the field, and his first published paper; his work in asphalt structure and rheology; his Naval service during World War II; work after the war at the Franklin Institute and Bendix Aviation; research at the National Asphalt Research Center with Wladimire Philippoff, Fred Gaskins, Jack Brodnyan, and Sam Muchnick, sponsored by the Army Chemical Center, DuPont, Esso and others; and where his rheological research in this area led to in other products such as adhesives, inks, plastic, rubber, detergents, and emulsions. He also discusses in some detail his non-scientific work of social significance.