In addition to Wilhelm Windelband and Heinrich Rickert, Emil Lask (1875-1915) is one of the most important representatives of neo-Kantianism of the so-called "Southwest German" school. This work is a collection of all of Lask's extant academic correspondence. It focuses on Lask's intense correspondence with his mentor Heinrich Rickert. This edition makes it possible to trace the development of Lask's thinking beyond his few publications, and it becomes clear to what extent Lask distanced himself from neo-Kantianism, for example by turning to Edmund Husserl's phenomenology. The correspondence also provides a multitude of insights into the university environment of the early 20th century.