Franz Marc and Paul Klee are among the few avant-garde artists of the 20th century who have gained significant popularity beyond the narrower circle of art enthusiasts. Their work is regularly showcased in international exhibitions, and both artists have recently been honored with their own museums: the Franz Marc Museum in Kochel and the Paul Klee Center in Bern. Less known is the fact that Marc and Klee shared an intense friendship. Although their relationship was short-lived due to Marc's early death in World War I, it was particularly significant for the development of both artists. This is exemplified by the fact that it was Marc who introduced Klee to the Munich art circles and assisted him in securing commissions – and that Klee restored Marc's major work 'Animal Destinies' after it was damaged in a fire following Marc's death. The exhibition at the Franz Marc Museum in Kochel, at Moritzburg in Halle, as well as at the Paul Klee Center in Bern, for which this volume was published, comprehensively documents the relationship between the two artists for the first time: their illustrated letters and cards, the works they gifted each other, the joint projects they planned, and the significant paintings created during those years in close collaboration. The volume is supplemented by essays from international experts.