MEDIA HOAXES <i> by Fred Fedler (Iowa State University Press: $19.95; 266 pp.) </i>

The Associated Press once ran a story about an Indian rebel leader named Siht El Otspueht. A few days later, after the rival United Press International--along with several newspapers--had picked up the story, AP revealed that the rebel leader was entirely fictitious--and his name backwards read “The UP Stole This.”

In presenting a history of media hoaxes, Fedler has compiled, in a sort of distortion-mirror image, a history of how the media have become respectable, and--saints preserve us!-- serious . In the good old days, as Fedler reports with relish, journalists were not above pulling a fast one now and then; it was fun, and it was good for ratings.

The study of hoaxes also is the study of mass psychology, and many a prankster has been taken aback by the dire results of his hoax. The public’s terror over Orson Welles’ broadcast of “War of the Worlds” is legendary. A similar incident occurred in 1874, when the New York Herald’s entire front page was occupied by a story of the dreadful destruction wrought by escaped animals from the Central Park Zoo. The perpetrators of the hoax had meant only to inform the public about changes needed at the zoo, and even spelled out in the last paragraph that the story was a fantasy scenario. But few read that far, and the city was in uproar as terrified citizens dashed for safety.

The book ends with a how-to chapter entitled “Fooling the Media for Fun and Profit.” Fedler does not write a scintillating style, but his stories come fast and furious--and they’re such a hoot that the author’s explanatory intrusions are easily tolerated.