Book excerpt: Joss Whedon’s Emmy award-winning musical tragicomedy tells the story of Billy, aka Dr Horrible, a budding supervillain who wants to beat superhero Captain Hammer and take over the world... and pluck up the courage to speak to his laundromat crush Penny. With exclusive new material from Joss and the production team, new photos, sheet music and more, this official book is a must for fans!