The Dark Tide Duology, penned by Michael A. Stackpole, encompasses the books The New Jedi Order: Dark Tide I: Onslaught and The New Jedi Order: Dark Tide II: Ruin. This pair of novels forms a section of the larger New Jedi Order series.
Initially, a third book was planned, but The New Jedi Order: Dark Tide: Siege was ultimately cut.
Both novels from the duology were released together as a single hardcover volume in June 2000, available solely through the Science Fiction Book Club.
ISBN 0-7394-1111-X Science Fiction Book Club Edition, released in June of 2000