Delirium is a 1998 novel by Douglas Anthony Cooper and is the second entry in his Izzy Darlow series.

The book was released by Hyperion in February 1998, and the Encyclopedia of Literature in Canada noted that it was "the first novel by an established author that was serialized on the Internet (Cooper began serializing the novel in 1994, shortly after the Web became widely available.

)"[1] Delirium has Izzy Darlow in New York, investigating the architect Ariel Price in order to write a biography about the man.

Price proves to be an unwilling subject, threatening to murder his biographer.

"[2] Quill and Quire expressed disappointment over Delirium, calling it "overwrought".