Mons Porphyrites, in the heart of the Red Sea mountains which dominate the Eastern Desert of Egypt, was the only source of imperial porphyry known to the ancient world. The quarries seem to have been worked from the Tiberian period until the early fifth century AD. A five-year programme of investigation of the quarries was undertaken between 1994 and 1998 and the first volume on the topography of the area appeared in 2001 (EES Excavation Memoir 67 by V. A. Maxfield and D. S. Peacock). This second volume includes reports of the excavations and provides a review of the overall development of the quarry complex.