according to the "suda", the "catalogue" was five books long. the length of each is unknown, but it is likely that the entire poem consisted of anywhere from 4000 to over 5000 lines. the majority of the content was structured around major genealogical units: the descendants of aeolus were found in book 1 and at least part of book 2, followed by those of inachus, pelasgus, atlas and pelops in the later books. it is believed that a rough guide to this structure can be found in the "bibliotheca", a roman-era mythological handbook transmitted under the name of apollodorus of athens which used the "catalogue" as a primary source for many genealogical details and appears to have followed the poem's overall arrangement.