Prof. Truesdell's criticisms of classical thermodynamics in 1952, followed by detailed presentation of its mathematical structure in 1960, reopened the subject to fundamental research. Truesdell taught at Indiana University 1950-61, where Walter Noll was his student. From 1961 until his retirement in 1989, Truesdell was professor of rational mechanics at Johns Hopkins University. He and Noll contributed to foundational rational mechanics, whose aim is to construct a mathematical model for treating (continuous) mechanical phenomena. Truesdell was the founder and editor-in-chief of the journals Archive for Rational Mechanics and Analysis and Archive for the History of Exact Sciences, which were unusual in several ways. Following Truesdell's criticisms of awkward style in scientific writing, the journal accepted papers in English, French, German, and Latin. In addition to his original work in mechanics, Truesdell was a major historian of science and mathematics, editing or co-editing six volumes of the collected works of Leonhard Euler.