Look through your discard pile. You may put a card from it onto your deck.
Harbinger is an Action card from the second edition of the base set. It is a cantrip that lets you move a card of your choice from your discard pile to your deck, allowing you to reuse that card without waiting for your next reshuffle.
 Official FAQ
- First draw a card and get +1 Action; then look through your discard pile, and you may put a card from it on top of your deck.
- Putting a card on top is optional.
 Other Rules clarifications
Harbinger is a cantrip, which usually favors engine-types of decks. However, the ability to put something from your discard on top of your deck is not that strong in deck-drawing engines. It is best in weak engines or Big Money without Terminal Draw. Also, it is stronger with cards that need many actions, for instance Conspirator or Vineyard.
- Big Money without terminal draw
In deck-drawing engines, Harbinger can become useless—there's likely to be nothing in your discard pile at any given time.
 English versions
|+1 Card. +1 Action. Look through your discard pile. You may put a card from it onto your deck.||Dominion 2nd Edition||October 2016|
 Other language versions
 Secret History