This book is an edition of the Athenian Constitution, the only one to survive of 158 Constitutions written in the school of Aristotle in the fourth century B.C., of which a text on papyrus was found at the end of the nineteenth century. Based on an edition commissioned by the Fondazione Lorenzo Valla in Italy, it provides an introduction, a re-edited Greek text with a facing translation, and a commentary.The editor has been engaged with this text throughout his working life, and published a large commentary on it in 1981 and a Penguin Classics translation of it in 1984: since then scholarly advances have continued, and he has been able to take advantage of them to bring the material in this book up to date. The translation aims at an accurate rendering of the Greek text; the commentary is based on the translation, and should be accessible to readers with little or no knowledge of Greek.