In this issue: COMMENT "Unclear Dangers", by Amy Davidson: The crisis in Baltimore. LIFE AND LETTERS "Outside In", by Kathryn Schulz: Nell Zink turned her back on the publishing world. It found her anyway. PROFILE "Lighting the Brain", by John Colapinto: Karl Deisseroth and the optogenetics breakthrough. BOOKS "Mirror Stage", by Malcolm Gladwell: A memoir of working undercover for the Drug Enforcement Administration. BOOKS "Anatomy of Error", by Joshua Rothman: A surgeon remembers his mistakes. THE CURRENT CINEMA "Distant Emotions", by Anthony Lane: Good Kill and Slow West.