Today they stand as enemies, but in the 1950s, few countries were as closely intertwined as Cuba and the United States. Thousands of Americans (including Ernest Hemingway and Errol Flynn) lived on the island, and, in the United States, dancehalls swayed to the mambo beat. The strong-arm Batista regime depended on Washington's support, and it invited American gangsters like Meyer Lansky to build fancy casinos for U.S. tourists. Major league scouts...