A depressive illness or a passing feeling? Mental detachment or a precursor to genius? Melancholy is a critical part of what it is to be human, yet everything from Prozac to self-help psychology books seem intent on removing all signs of sadness from contemporary existence. Complex and contradictory, melancholy's presence weaves through the histories of both science and art. This guide surveys literature, art, film, music and architecture, finding melancholy everywhere it turns.