Readers who enjoy nonfiction books about science and history may be interested in What I Left Out, a series of recurring features published by the excellent online magazine Undark. In What I Left Out, "book authors are invited to share anecdotes and narratives that, for whatever reason, did not make it into their final manuscripts." While these installments are not published on an entirely regular basis, each offers readers fascinating content to supplement the book at hand. One recent entry in the What I Left Out series is "Battling the Scourge of 'Embalmed Milk,'" in which Deborah Blum, author of The Poison Squad: One Chemist's Single-Minded Crusade for Food Safety at the Turn of the Twentieth Century, recounts the story of how two Indiana scientists helped turn the state into a national leader in public health at the turn of the twentieth century. Other authors featured here include Caroline Williams, David George Haskell, and Mary Roach. To date, there are more than two dozen What I Left Out installments, and more are sure to be added.