"A marriage of theory and practice"

During his life Leonhard frequently alternated between work in industry and academia. Alongside his academic career he was also active as a technician, engineer and businessman. The fact that he was awarded both an honorary doctorate by Vienna College of Technology and the Honorary Ring of the Association of German Electrical Engineers (VDE) reflects the recognition that Leonhard enjoyed in the industrial and academic world alike. Leonhard's work on control technology, which he developed between 1940 and 1965, and which has formed the basis of modern classical control technology, is of particular significance.