On the evening of October 30, 1938, a radio adaptation of H. G. Wells’s novella The War of the Worlds, directed and performed by Orson Welles and his Mercury Theatre on the Air, aired over the Columbia Broadcasting System (CBS). The hour-long program was structured to resemble interrupted news bulletins reporting an invasion by Martians in New Jersey and other locations. The format—musical interludes framed as commercial breaks, followed by increasingly urgent “dispatches”—led some listeners to interpret the dramatization as an actual unfolding emergency. Reports of frightened listeners, traffic jams, and people fleeing cities circulated widely in newspapers the next day. Some callers reportedly contacted police stations, newspapers, and radio stations seeking confirmation or urgent assistance. Particular confusion occurred where listeners tuned in after the initial disclaimers or heard segments presented as live news. Newspaper coverage emphasized episodes of panic, and several public officials criticized the broadcast for causing alarm. Historians note that reactions were uneven and localized: while some communities experienced significant alarm, others treated the program as entertainment. Research over subsequent decades has shown that the scale of the panic was likely exaggerated by newspapers, which had competing interests with radio and sensational headlines sold papers. Scholars who examined contemporary surveys, police records, and listener letters conclude that although genuine fear and disruption did occur in places, the number of people seriously affected was smaller than early reports suggested. The incident prompted debates about broadcasting responsibility and the power of mass media. Congressional hearings followed, and the Federal Communications Commission (FCC) reviewed the event, though it did not punish the network. Broadcasters and regulators discussed standards for program labeling and disclaimers to prevent similar confusion. The episode also became a case study in media effects, illustrating how format, context, and public anxiety can shape audience responses. Culturally, the broadcast secured a lasting place in American media history. It highlighted radio’s immediacy and persuasive power in an era before television and widespread media literacy. The War of the Worlds broadcast has since been analyzed in scholarship, dramatized and referenced in numerous works, and remembered both as a milestone in broadcasting and as an example of the complex interplay between media, audiences, and social context. While dramatic accounts of mass hysteria fueled by the program persist in popular memory, careful historical work stresses nuance: some listeners were genuinely alarmed, others were amused or critical, and contemporary reporting often amplified the extent of the panic. The October 30, 1938, broadcast remains an important episode for understanding the responsibilities of media producers and the dynamics of public reaction in moments of perceived crisis.