Darklands Trilogy was created in 2005.
Darklands - film - was created on 1997-11-26.
Darklands - video game - was created in 1992.
Beyond the Darklands - TV series - was created on 2009-03-18.
There is a third book, titled 'Daywards', but it's not scheduled for release by the University of Queensland Press until April 2010
The Bounty Trilogy was created in 1936.
Cairo Trilogy was created in 1956.
Larklight trilogy was created in 2006.
The Beaver Trilogy was created in 2001.
The Prodigal Trilogy was created in 2008.
Viking Trilogy was created in 1957.
Underworld Trilogy was created in 2010.
U.S.A. trilogy was created in 1930.