This book provides the only critical edition and English translation of Maḥmūd al-Jaghmīnī's al-Mulakhkhaṣ fī al-hayʾa al-basīṭa, the most widely circulated Arabic treatise on Ptolemaic astronomy ever written. Composed in the early 13^th century, this introductory textbook played a crucial role in the teaching, dissemination, and institutional instruction of Islamic astronomy well into the 19^th century (and beyond). Establishing the base text is a fundamental prerequisite for gaining insights into what was considered an...