Books VI and VII consider books of other authors (Theodosius, Autolycus, Aristarchus, Euclid, Apollonius, Aristaeus and Eratosthenes). Book VI deals with the books on astronomy which were collected into the Little Astronomy so-called in contrast to Ptolemy's Almagest or Greater Astronomy. As well as reviewing these works, Pappus points out errors which have somehow entered the texts.