This book, which includes the full Latin text and translation of a vital manuscript long thought lost, demonstrates that Alberic's famous treatise during the Eucharistic Controversy is a text that can be identified and has been known to scholars for years. By showing conclusively that this text was in fact written by Alberic, Radding and Newton transform our understanding not only of the particulars of the controversy and papal politics, but also of the intellectual process by which theological truths took shape in medieval Church councils.