Final answer:
The Cotton Club was a renowned Harlem jazz club that featured famous Black musicians and entertainers but only allowed white patrons, reflecting the racial contradictions of the 1920s.
Step-by-step explanation:
The key concept of the Cotton Club revolves around its role as a prominent jazz club in Harlem during the Jazz Age of the 1920s. Although it showcased some of the era's most famous Black musicians and entertainers such as Duke Ellington and Cab Calloway, the club maintained a racially discriminatory policy by only serving white patrons. This practice reflected the racial tensions and contradictions of American society at the time, as the club presented an "authentic" experience of African American culture to a white audience within a 'plantation atmosphere,' while excluding the very community it celebrated.