Dominion: Update Pack contains the seven new kingdom cards introduced in the second edition of Dominion, thereby allowing owners of the first edition to obtain these new cards without needing to repurchase the entire game.

The new cards: Harbinger, Merchant, Vassal, Poacher, Bandit, Sentry, Artisan

The following cards included in the first edition should be removed when using the second edition update pack.
Chancellor, Woodcutter, Feast, Spy, Thief, Adventurer