Aurel Kolnai was born in Budapest, in 1900 and died in London, in 1973. He was, according to Karl Popper and the late Bernard Williams, one of the most original, provocative, and sensitive philosophers of the twentieth century. Kolnai's moral philosophy is best described in his own words as "intrinsicalist, non-naturalist, non-reductionist," which took its original impetus from Scheler's value ethics, and was developed by using a natural phenomenologist method. The unique combination of linguistic analysis and phenomenology yields highly original ideas on classical fields of moral theory, such as responsibility and free will, the meaning of right and wrong, the universalisability of ethical norms, the role of moral emotions, internalism vs externalism, to mention a few. The volume presents a selection of essays by Kolnai, including his main political theoretical work, What is Politics About, available in English here for the first time. The second half of the book Kolnai's work is analyzed in a series of essays by eminent scholars.