Here we discuss the book entitled Ruins of Buddhistic Temples in Praga Talley: Tyandis Barabudur, Mendut and Pawon (available at archive.org/details/ ruinsofbuddhisti00gronrich), written by Isaac Groneman and published by H.A. Benjamins, Semarang, in 1912. We discuss in particular the Groneman s observations concerning the orientation of the temples, in reference to the path of the sun, and the descriptions of the statues, in particular those concerning the mudras of Buddha. As a reader can easily see, the Groneman s book is an outstanding report about the temples of Mendut, Pawon and Borobudur. It is essential for anyone who is studying the temples, not only for the scholars, but also for those persons which are fascinated by the Javanese antiquity.