This book presents new research on the histories and legacies of the German Expressionist group Blaue Reiter, the founding force behind modernist abstraction. For the first time Blaue Reiter is subjected to a variety of novel inter-disciplinary perspectives, ranging from a philosophical enquiry into its language and visual perception to analyses of its gender dynamics, its reception at different historical junctures throughout the twentieth century and its legacies for post-colonial aesthetic practices. The volume offers a new perspective on familiar aspects of Expressionism and abstraction, taking seriously the inheritance of modernism for the twenty-first century in ways that will help to recalibrate the field of Expressionist studies for future scholarship. Blaue Reiter still matters, the contributors argue, because the legacies of abstraction are still being debated by artists, writers, philosophers and cultural theorists today.