This book has both accidental origin and serious purpose. Its accidental origin was a conversation in Kyiv en route to a Byron conference in Armenia, when it was suggested that I might collect in one place some of the 50 or so articles I have written about Byron over the last 50 or so years. The tiny seed thus planted turned into the mustard tree proposed in the book’s title. For the Poems section, I have written five new essays. For the Life section, I am publishing two lectures for the first time, along with a slightly revised Byron Journal essay. The Politics section refashions three previously published pieces but the larger part of the book, and the dialogue with Gavin Hopps that rounds it off, is new.