It's as unofficial as Crystal Melody or any of those. But this is one that we don't have, so if you can rip the mp3s and make scans, that'd be awesome!
I've had pictures of this one from Yahoo! Auctions Japan for a long time (found the images in July 2006). The obi says NY-22 is the stock number, 1500 yen. The title "浜崎あゆみ作品集 (Hamasaki Ayumi sakuhin shuu, Ayumi Hamasaki Works Collection)" is what's shown on the spine.
This company, New York Records, did a second one as well, with "I am..." era songs on it. There's some info on it here:
http://www.otaru-orgel.jp/webshop/item/page_ny40.htm