This album is incredible. It's as good as their last two. I don't know how a band can continue to inovate after three albums especially in an age where music is so bland and sounds exactly the same.
John Frusciante plays on every track I believe and has backing vocals. I'm still trying to digest the album.
It sounds like the Stooges, Pink Floyd, Led Zeppelin, Frank Zappa, Captain Beefheart, Soundgarden, Sonic Youth, Miles Davis, Defunkt, and Jeff Buckley all got on stage created amazing music together.