The author begins the article by describing the major players in the Mafia crime families in the 1920s and 1930s before delving into an analysis of American Mafia family recruitment practices. A profile is offered of Salvatore Maranzano, one of the main players in the Castellammare War and the head of the Maranzano crime family. His background in Sicily and his immigration to the United States is described, followed by an examination of his engagement in the smuggling of immigrants from Sicily into the United States, mainly to supplement his growing crime army. The major themes of the Castellammare War are discussed and corrections of past research on this war are offered. The discussion incorporates the financing of the war, the key wartime murders, the overall death toll, and the war’s outcome, which ended when Giuseppe Masseria was murdered in 1931, leaving Maranzano the head of the U.S. Mafia and arguably leading to the development of the current American Mafia structure. Before long, Maranzano and his Sicilian colleagues were killed en masse by Salvatore Luciano, another major Mafia player who wished to develop a more “Americanized” Mafia. It has been widely argued that the result of this “purge” of Sicilian crime actors from the Mafia formed the foundation for the current American Mafia crime group. The author, however, outlines the actual complexities involved in the formation of the current American Mafia structure, arguing that much of the so-called purge tale was largely fabricated and blown out of proportion. The author further argues that the Castellammare War was actually a revolt against centralized power in the Mafia and that the war resulted in the destruction of the divisive “boss of bosses” system and the establishment of the “Commission” in 1931 as an agency for consensus. Footnotes