Like spies Aldrich Ames and Robert Hanssen before her, Ana Montes blindsided her colleagues with brazen acts of treason. For nearly 17 years, Montes succeeded in two high-stress jobs. By day, she was one of the government's top Cuba experts, a buttoned-down GS-14 with shockingly easy access to classified documents. By night, she was on the clock for Fidel Castro, listening to coded messages over shortwave radio, passing US secrets to handlers in local restaurants, and slipping into Havana wearing a wig. In Code Name Blue Wren, investigative journalist Jim Popkin weaves the tale of two sisters who chose two very different paths, plus the unsung heroes who had to fight to bring Ana to justice.