This book provides a new all-round perspective on the life and work of Edgar Zilsel (1891-1944) as a philosopher, historian, and sociologist. He was close to the Vienna Circle and has been hitherto almost exclusively referred to in terms of the so-called “Zilsel thesis” on the origins of modern science. Much beyond this “thesis”, Zilsel’s brilliant work provides original insights on a broad number of topics, ranging from the philosophy of probability and statistics to the concept of “genius”, from the issues of scientific laws and theories to the sociological background of science and philosophy, and to the political analysis of the problems of his time. Praised by Herbert Feigl as an “outstanding brilliant mind”, Zilsel, being as a Social-Democrat of Jewish origins, mostly led a life of hardship marked by emigration and coming to a sudden and tragic end by suicide in 1944. The impossibility of an academic career has hindered the reception of Zilsel’s scientific work for a longtime. This volume is a contribution to its late reception, providing new insights especially into his work during his years in Vienna; moreover, it shows the heuristic value of Zilsel’s ideas for future scholarly research – in philosophy, history, and sociology.