Sonny is the eldest son of Don Vito Corleone and one of the novel’s principle protagonists. In contrast to his father’s even-tempered demeanor and tendency to make violence a last resort, Sonny is hotheaded, impetuous, and quick to use violence to resolve a dispute. Sonny is also lascivious and known for his extremely large phallus. Despite being married to Sandra, Sonny openly has an affair with Lucy Mancini and other women. Sonny’s bad temper and high libido often clouds his judgment. As a result, Vito thinks Sonny is unsuited to succeed him as Don of the Family, a role that demands cool judgement and forethought. Born in Manhattan, the young Sonny witnesses Vito’s murder of Fanucci, a key moment that baptizes him into the “Family business.” As a teenager, Sonny works as a violent enforcer for his Family when the Corleones are at war with the other Mafia families. His temperamental issues notwithstanding, Sonny becomes “acting boss” of the Corleone Family after Sollozzo and Phillip Tattaglia nearly murder Vito after the latter refuses a role in Sollozzo’s drug racket. Although Sonny’s temper leads him to demand revenge, Tom Hagen convinces Sonny to negotiate with Sollozzo and his police protector, McCluskey. Sonny proves a fairly capable leader, as demonstrated by his role in sanctioning Michael’s murder of both Sollozzo and McCluskey. Ultimately, however, Sonny’s temper leads to his demise after an attempt to kill Carlo for beating up Connie, Sonny’s sister, leads to his assassination at the hands of Don Barzini’s hitmen. Sonny’s death demonstrates the pitfalls of impulsiveness in a criminal subculture that rewards patience and deft negotiation.