Rook is the name of a group of games and of the special deck of cards for the game which was introduced by Parker Brothers in 1906. The games are popular in Eastern Kentucky, in the Mennonite communities of Southern Ontario (near Elmira / Waterloo), Manitoba, Pennsylvania and Ohio, and probably also in other parts of North America.
It is likely that Rook cards were introduced for the benefit of members of fundamentalist protestant religions, such as the Mennonites, who considered (and in some cases still consider) playing cards to be the "devil's tool". They were forbidden to play cards; but Parker Brothers filled the void with a game that was played like cards but did not use the standard playing card deck. There are people who refuse to play any cards with a standard deck but who will happily play Rook all night every weekend. There is a close parallel here with Kvitlech cards, which were playing cards bearing numbers, made for use by Central European Jews who were also forbidden by their religion to use standard cards.
The deck normally comes with a booklet describing a number games which can be played with the cards. The main group of games are point trick games with trumps and bidding. The cards in each suit rank from 14 (high) to 1 (low) and the counting cards are generally the 14 and 10 of each suit (worth 10 points each) and the 5 (worth 5 points). The Rook card, when used, is worth 20, and is generally an extra trump. In some games the 1 is promoted to rank above the 14 and is worth 15 points.
On this web page, I describe two Rook games, Kentucky Rook and Call Partner Rook, neither of which is exactly like any of the games described in the book provided with the cards (at least not in any edition I have seen). If players of these or other variations of Rook would like to let me know the details of the versions they play, I would be happy to add this further information to the page.
*Information courtesy of John McLeod