Nice. I, personally, am having a hard time gauging the power level of the card. However, I am sure you will receive a lot of feedback on this one. My gut tells me it's undercosted. It may end up needing to be a sorcery. I guess it's comparable to
Meditate, so perhaps a 2U instant is do-able. Your drawback is arguably more harsh to combo than Meditate's drawback. The wording is just about right (obviously drawn from
Brainstorm), I suggest:
Draw four cards, then put four cards from your hand on the bottom of your library.
(I don't see how the "in any order" really makes a difference. See
Impulse.)