Dominion (Card Game) Wiki
Type Action - Attack
Effect Each other player reveals the top 2 cards of his deck. If they revealed any Treasure cards, they trash one of them that you choose. You may gain any or all of these trashed cards. They discard the other revealed cards.
Cost 4 Coins
Set Dominion: Base Set
Illustration Julien Delval

Additional Rules from the Rulebook[]

A player with just one card left reveals that last card and then shuffles to get the other card to reveal (without including the revealed card); a player with no cards left shuffles to get both of them. A player who still doesn't have two cards to reveal after shuffling just reveals what he can. Each player trashes one Treasure card at most, of the attacker's choice from the two revealed cards, and then you gain any of the trashed cards that you want. You can only take Treasures just trashed—not ones trashed on previous turns. You can take none of them, all of them, or anything in between. Put the Treasures you decided to gain into your Discard pile. The ones you choose not to gain stay in the Trash pile.

The Secret History of Thief[]

In an article on Board Game Geek, Donald X. Vaccarino commented on the development of Thief:

This is the only card that Valerie and Dale changed (other than non-functional wording changes). Which is of course just the way I would have wanted things - I mean who wouldn't? They had no compulsion to make changes for the sake of changing things; they complained about a few weak/confusing cards that just left, and everything else but Thief ended up the way I made it. Anyway Thief originally revealed the top 2 cards, then put the untrashed ones back. Valerie didn't like how, if you got hit with Thief and your top 2 cards were non-Treasures, then subsequent Thieves would also get nothing. Also there was the issue of remembering the order to put the cards back. So they changed it from reveal to reveal-then-discard. I was initially skeptical but in the end I think it was a good change.[1]