Millstone
Artifact
, 
: Target player mills two cards.
Minds, like mountains, are never so grand and mighty that they can't be reduced to dust.
Yeong-Hao Han
Rulings
Since you are putting more than one card in the graveyard at one time, the affected player can choose the order the 2 cards go in.
(wotc • 2004-10-04)
Can be used on a player with less than 2 cards in their library. It will remove 0 or 1 cards if that is all that is available.
(wotc • 2004-10-04)
It is not a draw effect so it will not cause a player with less than 2 cards in their library to lose.
(wotc • 2004-10-04)
Rulings
Since you are putting more than one card in the graveyard at one time, the affected player can choose the order the 2 cards go in.
(wotc • 2004-10-04)
Can be used on a player with less than 2 cards in their library. It will remove 0 or 1 cards if that is all that is available.
(wotc • 2004-10-04)
It is not a draw effect so it will not cause a player with less than 2 cards in their library to lose.
(wotc • 2004-10-04)