Text (US+errata): {3}: Each player puts the top two cards of his or her library into his or her graveyard. [Oracle 2007/05/01]
Can be used if a player has less than 2 cards in their library. It will remove 0 or 1 cards if that is all that is available. [D'Angelo 1998/10/15]
It is not a draw effect so it will not cause a player with less than 2 cards in their library to lose. [D'Angelo 1998/10/15]
Since you are putting more than one card in the graveyard at one time, each affected player can choose the order the 2 cards go in. [D'Angelo 1998/10/15]