The eponymous protagonist, Laurent Michaelmas, is an ex-hacker who had, early in the computer era, left back doors in many key pieces of software which run vital government & commercial computers. As a result, by the turn of the millennium, he's become one of the most powerful men on earth, because of his ability to spy & influence through the world wide computer network.

By the time of the novel, Michaelmas has successfully used his power to create & sustain a powerful version of the UN to ensure world peace. He stays in the background, however, as a journalist, albeit a highly influential & respected one whose opinions can still influence public opinion. However, as the novel progresses, he slowly learns that a possible extraterrestrial presence may be interfering with the new world he has worked so hard to create.

The novel is remarkable for its prescience, because it appeared less than a decade into the Internet era, long before its current prominence & ubiquity. Its description of journalism & its professional culture are likewise highly developed, mainly due to the late Budrys' residence near Northwestern University's Medill School of Journalism, which appears in the book.