1920s: New technologies such as radio, the automobile, and motion pictures enhance communication and build a national community.

Today: New technology such as the Internet, wireless communications, and broadband information technology enhance communication and help create a global community.

1920s: Women are able to vote for the first time, though they do not yet find themselves in places of political influence.

Today: Women are represented at all levels of state, local, and federal government except the presidency. Women are in the Congress, the Cabinet, and the Supreme Court.

1920s: African-American writers, composers, and performers flock to New York City, leading to the Harlem Renaissance, the first sustained literary and artistic movement of African Americans in a predominantly segregated society.

Today: African-American writers, musicians, actors, and entertainers are among the highestpaid members of their professions, appealing to all racial groups.

1920s: Jazz music permeates the...