The fifth installment in the immensely popular dominion series. Prosperity adds 25 new kingdom cards, as well as the Colony (victory) and Platinum (treasure) cards. These can increase the play time (as well as the scores). The theme is big money and big actions.
The Dominion rules are extraordinarily comprehensive. For questions regarding how cards interact, if you can, check the individual card entries in the appropriate rulebook(s) and you'll probably find your answer there. A PDF of the Dominion: Prosperity rules is available here.