[There's a note seemingly taped to the front door of Clow's apartment, fine stationary with elegant script on the front. Anyone who isn't the intended recipient will find it surprisingly difficult to remove, although if you've got a fair bit of a magical power, you'll eventually be able to pry it down and open it. The front of the envelope reads:]
Mr. Anthony J. Crowley
My dearest Crowley,
My apologies for not doing this in person, but I detest goodbyes. They always seem so pointless - it is simply time for me to move on. Should you wish to use it, this apartment is still in my name, and the space enchantment is permanent. The librarian construct will probably start to fade in a few weeks, although it should be simple to renew if you have the talent. There's a portal door in the back of the study - I think it's more interesting if I leave figuring out how that works to you. However, if you misuse it - believe me, I will know.
Best wishes,
Clow Reed