The sun temples of the Fifth Dynasty are an unparalleled monument of ancient Egypt which characterized the central part of the Old Kingdom, usually considered as the apex of the solar cult and theology. Yet, the issues of their actual meaning, original architectural shape and ideological influence on the later phases of Egyptian history are far from clear, as well as their cultic, ideological and symbolic relationship with the contemporary pyramids and with what is considered to be the original place of rise and diffusion of the solar cult in ancient Egypt, i.e., the city of Heliopolis. Six temples were built in a quite limited time span in the middle of the Third Millennium BC but only two have been discovered so far. Where are, thus, the missing ones? All these questions, and many others, are addressed by the present book, which represents the first complete publication on the sun temples matter. The volume collects all the available archaeological and textual evidences related to these monuments, including an in-depth reconstruction of the original decoration of the temples and a rich prosopography of the people involved with their running. Several tables, sheets and plates, with photographs of the monuments and the main related documents, also enrich the publication.