Although Ptolemy's "Harmonics" never had the influence of his "Almagest" or "Geography", it is nonetheless a well-structured treatise and contains more methodological reflections than any other of his writings. It also exherted a strong influenced during the Renaissance and the seventeenth century; Kepler, for instance, read and was influenced by this work in his own musings on the harmony of the world ("Harmonice Mundi", Appendix to Book V).