As Curley's wife implies, these three men are social outcasts. They remain behind when the other ranch hands travel into town for drink and women. Candy, Crooks, and Lennie are all crippled: Candy lost a hand in an accident with some machinery, Crooks has an injured back, and Lennie is "slow" mentally. These physical and/or mental challenges have caused them to be placed on the periphery of the social order. They do not easily fit in with the others and are able to bond, albeit for only a brief time, when they are all in Crooks' room in Section 4.
