This is the definitive collection of the ethical work of the great Oxford moral philosopher H. A. Prichard (1871-1947). Prichard is famous for his ethical intuitionism: he argued that moral obligation cannot be reduced to anything else, but is perceived by direct intuition. The essays previously included in the posthumous collection are now augmented by a selection of previously unpublished writings from Prichard's manuscripts, allowing for the first time a full view of his distinctive contribution to moral philosophy, at just the time when intuitionism is enjoying a revival of interest.