"The Almagest" (by Ptolemy)

"The Almagest," written by Claudius Ptolemy in the 2nd century, is a foundational astronomical treatise that systematically describes the motions of stars and planets. It presents a geocentric model, placing Earth at the universe's center, with planets moving in complex paths called epicycles and deferents to explain their observed behaviors. The work compiles and analyzes existing astronomical knowledge, offering mathematical models for predicting celestial events. It served as the authoritative guide to astronomy for centuries, shaping scientific thought until the heliocentric model replaced it. Overall, "The Almagest" is a significant milestone in ancient scientific understanding of the cosmos.