WizarDru
Adventurer
Concerning the Call of Chthulu Model; the core rules has had the following editions:
Call of Cthulhu, 1st Edition (1981)
Call of Cthulhu Designer's Edition (1982)
Call of Cthulhu, 2nd Edition (1983)
Call of Cthulhu, 3rd Edition (1986)
Call of Cthulhu, 4th Edition (1989)
Call of Cthulhu, 5th Edition (1992)
Call of Cthulhu 5.5 (1998)
Call of Cthulhu 5.6 (2000)
Call of Cthulhu 20th anniversary edition (2001)
Call of Cthulhu Miskatonic University edition (2001)
Call of Cthulhu, 6th Edition (2004)
Call of Cthulhu 25th anniversary edition (2006)
In addition, the following editions were published:
Delta Green - 1997
CoC d20 - 2001
Delta Green d20 - 2007
Trail of Chthulu (GUMSHOE) - 2008
Shadows of Chthulu (True20) - 2008
Realms of Cthulu (Savage Worlds) - 2009
Not much change from edition to edition, but they certainly did keep publishing them.
Call of Cthulhu, 1st Edition (1981)
Call of Cthulhu Designer's Edition (1982)
Call of Cthulhu, 2nd Edition (1983)
Call of Cthulhu, 3rd Edition (1986)
Call of Cthulhu, 4th Edition (1989)
Call of Cthulhu, 5th Edition (1992)
Call of Cthulhu 5.5 (1998)
Call of Cthulhu 5.6 (2000)
Call of Cthulhu 20th anniversary edition (2001)
Call of Cthulhu Miskatonic University edition (2001)
Call of Cthulhu, 6th Edition (2004)
Call of Cthulhu 25th anniversary edition (2006)
In addition, the following editions were published:
Delta Green - 1997
CoC d20 - 2001
Delta Green d20 - 2007
Trail of Chthulu (GUMSHOE) - 2008
Shadows of Chthulu (True20) - 2008
Realms of Cthulu (Savage Worlds) - 2009
Not much change from edition to edition, but they certainly did keep publishing them.