This text describes the native (men and women under distinct rubrics) of the twelve zodiacal signs in twelve chapters preceded by a preface. The title Liber Ptholomei peritissimi astrologi de nativitatibus hominum occurs only in one manuscript (Munich, BSB, Clm 25009), but the last sentence of the preface makes it clear that the work derives its substance from a book by Ptolemy: ‘secundum quod reperitur in libro Ptholomei peritissimi astrologi’. Four manuscripts (London, WL, 2; Paris, BnF, lat. 7016A; Paris, BnF, lat. 7817; Vatican, BAV, Vat. lat. 11253) have an additional chapter at the beginning on how to determine the sign of birth by onomancy (‘Ad inveniendum signum nativitatis cuiuslibet hominis, recipe nomen eius et nomen sue matris…’). Two manuscripts (Nürnberg, GNM, 42296, and Wolfenbüttel, HAB, 784 Helmst. (875)) have an expanded version with further characteristics of the sign added at the beginning and at the end of each chapter. Texts describing the native of the twelve signs have a long history since Antiquity and at least one version circulated under the names of Hermes and Ptolemy in Arabic, the Kitāb Mawālid al-rijāl ʿalā raʾy Harmis wa-Baṭlamiyūs for men and the Kitāb Mawālid al-nisāʾ ʿalā raʾy Harmis wa-Baṭlamiyūs for women (see F. Sezgin, Geschichte des arabischen Schrifttums, VII: Astrologie – Meteorologie und Verwandtes, Leiden, 1979, 46, nos 5-6; also M. Ullmann, Die Natur- und Geheimwissenschaften im Islam, Leiden, 1972, 284).