Following the 1957 season, two of baseball’s most famous teams, the Brooklyn Dodgers and the New York Giants, left New York City and headed West. Those events have entered baseball lore as acts of betrayal committed by their greedy owners: Walter O’Malley of the Dodgers and Horace Stoneham of the Giants. But that is only one side of the story. Mitchell argues that those moves to California forged Major League Baseball (MLB) as we know it today, second in influence only to Jackie Robinson’s debut in 1947. By moving two teams with national reputations and well-known players, MLB broadened its fan base. This was particularly important following a decade that was plagued with moribund franchises, low wages and the difficult dismantling of big league baseball's apartheid system.

In the years immediately following the moves, the two most iconic players of the 1960s, Sandy Koufax and Willie Mays, had their best years, bringing even greater fame to their ball clubs. The Giants also played an instrumental role in the first phase of baseball’s globalization by bringing in players from Latin America, while the Dodgers set attendance records and pioneered new ways to market the game.