Gerhard Ertl received the 2007 Nobel Prize in Chemistry in recognition of his major contributions in the field of surface science. This includes studies of fundamental molecular processes at the gas-solid interface and the methodological foundations for an entire field of research. This paper provides a personal view of his research, including remarkable characteristics, surface elementary steps, from adsorption isotherms to chemical oscillations, visualized surface reactions, and a new approach to surface reactions. It also describes the research environment in Germany.