The story of artist R. H. Quaytman’s discovery of an engraving hidden behind a famous artwork by Paul Klee. This book begins with artist R. H. Quaytman uncovering something startling about a picture by Paul Klee. Pasted beneath Klee’s 1920 Angelus Novus—famous for its role in the writings of its first owner, Walter Benjamin—Quaytman found that Klee had interleaved a nineteenth-century engraving of Martin Luther, leaving just enough visible to provoke questions.