The Mask Trilogy is a group of games created by Wolfgang Kramer and Michael Kiesling. All of the games in the Mask Trilogy make use of the Action Point Allowance System. They all have a mask on their cover, hence the nickname.
Torres is considered by many to be an informal member of the Mask Trilogy because of its similarities to the other games, Tikal in particular. It would probably be a formal member if it weren't for the fact that it doesn't have a mask on its cover.