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From MTV.com:

"The mixtape is not really focusing on his singles," said Cee — Bad Boy's Greatest Hits disc, dropping Tuesday, will serve that purpose. "You're not gonna hear 'Hypnotize' and those type of records, but it's focusing on guest appearances. All the guest appearances he's ever appeared on. Original versions. Nothing remade, original duets he's done with other artists. Then you have the freestyles he's done. The freestyles done with me or other DJs like DJ Enuff, Funk Master Flex. Then also, there's some original versions to songs. There's some songs you're gonna hear that you've heard the album versions, but you never heard it with the original track.

"There's also some live stuff," he added. "Live from Madison Square Garden, Philly, London. It just really shows the short amount of time Biggie was here, the amount he's done. It's over 70 songs and a double-CD. I also want to big up my man DJ Whoo Kid. He's been helping me out to get back in the fold of doing what I gotta do to get back out in the mixtape circuit. It's probably gonna be the last mixtape I ever do. I hope people cherish the way I am."

It's called "The Best of Biggie: 10th Anniversary Mixtape".