The beginning of commercial radio broadcasts in 1920 brought a new source of information and entertainment directly into American homes. President Franklin Roosevelt understood the usefulness of radio as a medium of communication: His "fireside chats" kept the nation abreast of economic developments during the Depression and of military maneuvers during World War II.

The widespread availability of television after World War II caused radio executives to rethink their programming. Radio could hardly compete with television's visual presentation of drama, comedy, and variety acts; many radio stations switched to a format of recorded music mixed with news and features. Starting in the 1950s, radios became standard accessories in American automobiles. The medium enjoyed a renaissance as American commuters tuned in their car radios on the way to work.

The expansion of FM radio, which has better sound quality but a more limited signal range than AM, led to a split in radio programming in the 1970s and 1980s. FM came to dominate the music side of programming, while AM has shifted mainly to all-news and talk formats.

Barely in existence 25 years ago, talk radio usually features a host, a celebrity or an expert on some subject, and the opportunity for listeners to call in and ask questions or express opinions on the air. The call-in format is now heard on nearly 1,000 of the 10,000 commercial radio stations in the United States.

Despite the importance of TV, the reach of radio is still impressive. In 1994, 99 percent of American households had at least one radio, with an average of five per household. Besides the 10,000 commercial radio stations, the United States has more than 1,400 public radio stations. Most of these are run by universities and other public institutions for educational purposes and are financed by public funds and private donations. In 1991, more than 12 million Americans listened each week to the 430 public radio stations affiliated with National Public Radio, a nationwide, nonprofit organization headquartered in Washington, D.C.

• An Annual Report on American Journalism :Radio
• Early Radio History 1897-1927 : Articles and Extracts
• The State of the News Media :Radio

• Internet Public Library - Radio
• Museum of Broadcast Communications
• National Association of Broadcasters
• National Public Radio
• PBS Newshour
• Radio-Television News Directors Association & Foundation
• TVRadioWorld - USA
• Voice of America News and Newswire