TopDeck?

[FrancescodiMeeple]

Sometimes i get the message that I may Topdeck. What does this mean?

[Ingix]

It means you put a card on Top of your Deck. An example would be Artisan:

Gain a card to your hand costing up to $5.
Put a card from your hand onto your deck.

In this case, the card comes from your hand, but sometimes it comes from other places.