Tool: Danny Carey, Adam Jones , Justin Chancellor, Maynard James Keenan.Audio Mixer: Joe Barresi.Recording information: Grandmaster, Hollywood, CA; O'Henry, Burbank, CA; The Loft, Hollywood, CA.Animation: Ray Zone.Illustrator: Alex Grey.Photographer: Travis Shin.To its legion of fans, everything the band Tool does is an event, but the elaborate plan behind their sporadic release schedule--roughly five years, on average, between albums--is due primarily to the time and effort the band packs into each successive effort. To title their fourth album 10,000 DAYS, then, isn't as much an exaggeration as it would seem. Tool are America's most consummate mainstream perfectionists, revitalizing progressive rock to the grandeur of its '70s heyday, but updated with technocratic tension and existential dread not known to previous generations. Perhaps it's the development of more musical genres at the turn of the millennium, but it's also Tool's ability to take what is needed from each and leave the florid excesses behind, forming a seething gray core of angst and release across epic-length songs that are as accessible as they are complex. The material on 10,000 DAYS provides typically thought-provoking grist for the band's lyrical handwringing ("Vicarious" tackles reality television as the bane of culture; "Wings for Marie" is a two-part suite on the death of vocalist Maynard James Keenan's mother), and is as musically engaging as ever, finding the band at their most powerful since 1996's AENIMA.