In "Hagarism: The Making of the Islamic World" (1977), Cook and his associate Patricia Crone provided a new analysis of early Islamic history by studying the only surviving contemporary accounts of the rise of Islam. They fundamentally questioned the historicity of the Islamic traditions about the beginnings of Islam. Thus they tried to produce the picture of Islam's beginnings only from non-Arabic sources. By studying the only surviving contemporary accounts of the rise of Islam, which were written in Armenian, Greek, Aramaic and Syriac by witnesses, they reconstructed a significantly different story of Islam's beginnings, compared with the story known from the Islamic traditions. Cook and Crone claimed to be able to explain exactly how Islam came into being by the fusion of various near eastern civilizations under Arabic leadership. Later, Michael Cook refrained from this attempt of a detailed reconstruction of Islam's beginnings, and concentrated on Islamic ethics and law. Patricia Crone later suggested that the book was “a graduate essay" and "a hypothesis," not "a conclusive finding.”