INTRODUCTION: Geography and Geology; Historical Outline; Archaeological Research; THE ARCHAEOLOGICAL SITES: PREHISTORIC THERA: AKROTIRI: The Houses; Pottery; Wall-Paintings; Stone Tools and Vessels; Miniature Art and Metal-Working; External Relations; Economic, Social, and Political Organisation; The Catastrophe and the Myth of Atlantis; ANCIENT THERA: MESA VOUNO: Town Plan; Architecture; The Agora; The Sanctuaries; Other Public Buildings; Private Houses; Art and Letters; Funerary Customs; External Relations; Social Organisation and Way of Life; TOUR OF THE ISLAND: Phira; Merovigli; Oia; Vothonas; Pyrgos; Prophitis Ilias; Mesa and Exo Gonia; Akrotiri; Emborion.