The Greek inscription of the Epicurean Diogenes is the longest known from the ancient world and the only one to expound a complete system of philosophy. Its author, a wealthy citizen of the upland city of Oinoanda (southwest Turkey), set it up during the reign of Hadrian (117-138) to broadcast a message of moral healing and salvation urbi et orbi - to the city and the world. He addresses Oinoanda's citizens in his time and time to come, and also so-called foreigners, who, he says, are actually our fellow citizens in a world which is one country and home for humanity. Fragments of Diogenes' work were discovered in 1884-1889. Further investigations were inaugurated by Martin Ferguson Smith in 1968-1973 and continued during British and German-led surveys (1974-2017). The number of known pieces of the inscription more than tripled, from 88 in the 19th century to 305. This translation, the first in English to include all the latest discoveries and research, is intended for all who are interested in philosophy, in the intellectual and cultural history of the Greek world under the Roman Empire, and in the story of an impressive and moving human document. If it also benefits anyone in need of "the medicines of salvation", so much the better. Diogenes' message is addressed to us no less than to his contemporaries, and the Epicurean ethical ideal of ataraxia, "freedom from disturbance" or "tranquillity of mind", achieved through the elimination of unnecessary fears and desires, is as relevant today as it was two millennia ago.