Wilfrid Sellars was and remains one of the most prominent and important twentieth-century philosophers: his writings played a key role in shaping the philosophical agenda in the English-speaking world during the second half of the 20th century, and they remain an active focus of intense critical attention and lively discussion. Jay Rosenberg studied under Sellars in the early 1960s, was continuously engaged with his work for over forty years, and was widely regarded both as its foremost expositor and as one of Sellars' truest disciples. This was the last book that Rosenberg completed before his death at the age of only sixty-five. In it he gathers previously published studies of the central elements and implications of Sellars' philosophy, along with three new essays that further highlight and articulate the significance of his work, both historically and with respect to contemporary debates.