Professor Mesinger’s research has focused on the fundamental theory and practical implementation of numerical methods for atmospheric prediction, particularly energy-conserving finite-difference schemes, terrain-following coordinate systems, and planetary boundary-layer parameterisation. In 1973, he developed the original code for the HIBU (Hydrometeorological Institute and Belgrade University) model in collaboration with Zaviša Janjić. Following its introduction to the U.S. National Meteorological Center in 1984, the model evolved into the Eta model, which became a principal operational regional weather-prediction system in the United States and subsequently gained widespread international application. His identification of the pressure-gradient-force convergence problem associated with sigma-coordinate systems led to the development of the step-mountain “eta coordinate”, which substantially reduced spurious numerical effects over steep terrain and influenced the design of subsequent atmospheric models. His 1976 monograph, Numerical Methods Used in Atmospheric Models, co-authored with Akio Arakawa, remains a classic reference in numerical atmospheric modelling. His selected works address developments of the Eta model, comparisons of eta and sigma coordinate formulations, the North American Regional Reanalysis, planetary boundary-layer parameterisation in numerical weather prediction, and precipitation forecast verification. Collectively, these contributions reflect a sustained scientific legacy connecting fundamental dynamical meteorology with numerical modelling methodologies that have made a lasting contribution to operational weather forecasting.