Photos by Leandro Viana document how the roughly 2,500 Sherpas in New York City strive to maintain their culture.

In Undisclosed Files of the Police: Cases from the Archives of the NYPD (Black Dog & Leventhal Publishers), the authors—a lieutenant with the department since 1981, a retired detective and true-crime writer and The New York Post’s veteran crime reporter—chronicle the most interesting, most notorious, most unbelievable, or most disturbing crimes in city history.