The commentary to this edition of the Protagoras of Plato is in the main a translation of that of the fourth German edition by the venerable and distinguished scholar, Dr. Hermann Sauppe, Pro fessor in the University of Gottingen and Privy Councillor of State. The critical notes have been somewhat abridged, and the commentary has received such additions as seemed needful for those students who begin the study of Plato with this dialogue. The American editor trusts that the extreme pleasure which he has found in the preparation of this volume will be shared by those who shall here meet the Platonic Socrates. He makes grateful acknowledgments to Professor Sauppe for his very cor dial permission to give to American students the use of his ad mirable work; and expresses his thanks to Professor Seymour.