Prof. Jack has been trained as an immunologist in Prof Klaus Rajewsky´s lab in Cologne, and worked in developmental biology at Prof. Walter Gehring´s lab in Basel; subsequently, he has been Professor for Immunology for many years at the University of Greifswald. For more than 10 years, he has been active in the organizing committee of the Spring School for Immunology of the Deutsche Gesellschaft für Immunologie. Though retired meanwhile, he still gives introductory lectures at the Spring and Autumn School, and a lecture on Concepts in Immunology at Uni Greifswald.