Presence of the Librarian

At the beginning of your end step, you may
draw two additional cards. You may choose to
place one Green or Forest card, from among
them on he bottom of your library. For any
remaining, pay 4 life or put the card on top of
your library.
"Any Librarian can get you a book. A good one can
keep you from picking bad books. Only a great one
can give you the one you the book you don't know
you need yet."