Jochen Hoefs has been working in the field of stable isotope geochemistry of the elements hydrogen, lithium, carbon, oxygen and sulfur since 1965. His main scientific interests include the stable isotope geochemistry of the mantle and lower crust, the genesis of basaltic and granitic magmas, water/rock interactions under hydrothermal conditions, the history of the ocean and the atmosphere and the application of stable isotopes to environmental problems. He has published about 150 scientific papers, mostly in international journals.