The Surface Decarburization of Steel at Heat-Treating Temperatures, authored by W.E. Jominy, is a detailed investigation into the factors influencing the decarburization processes occurring in steel during heat treatment. The study, sponsored by the American Gas Association, explores the impact of various furnace atmospheres, pressures, temperatures, and exposure periods on the decarburization of steel surfaces. Through meticulous experimentation, including the effects of different gases and gas mixtures, the research delves into how elements like steam, carbon dioxide, air, nitrogen, and hydrogen contribute to decarburization. The analysis concludes that environmental conditions such as gas composition and atmospheric pressure critically affect the steel's surface properties, potentially leading to diminished material performance. This work provides insights for predicting and mitigating decarburization, vital for maintaining the surface hardness of steel in industrial applications. This bulletin offers invaluable guidance to engineers seeking to optimize steel heat treatment processes.