Giordano Bruno’s The Ash Wednesday Supper is the first of six philosophical dialogues in Italian that he wrote and published in London between 1584 and 1585. It presents a revolutionary cosmology founded on the new Copernican astronomy that Bruno extends to infinite dimensions, filling it with an endless number of planetary systems. As well as opening up the traditional closed universe and reducing earth to a tiny speck in an overwhelmingly immense cosmos, Bruno offers a lively description of his clash of opinions with the conservative academics and theologians he argued with in Oxford and London. This volume, containing what has recently been claimed as the final version of Bruno’s Ash Wednesday Supper, presents a new translation based on a newly edited text, with critical comment that takes account of the most current discussion of the textual, historical, cosmological and philosophical issues raised in this dialogue. It considers Bruno’s work as a seminal text of the late European renaissance.