This is a record that even those who aren't Deep Purple fans can listen to two or three times in one sitting – but then, this wasn't much like any other album that the group ever issued. Actually, Deep Purple was highly prized for many years by fans of progressive rock, and for good reason. The group was going through a transition – original lead singer Rod Evans and bassist Nick Simper would be voted out of the lineup soon after the album was finished (although they weren't told about it until three months later), organist Jon Lord and guitarist Ritchie Blackmore having perceived limitations in their work in terms of where each wanted to take the band.

Deep Purple have never quite been placed in the revered 1960s canon that includes the Who, Pink Floyd, Led Zeppelin, or any of the other British rock bands who continue to reunite in various configurations to tour and even periodically release new albums, but given that the group has always been a riveting and brilliant live act, part prog, part heavy metal, part funky R&B, and imminently theatrical, that second-tier designation seems like both an oversight and a shame. Returning with this set, the band's first since 2005's Rapture of the Deep, and featuring a near-classic lineup of vocalist Ian Gillan, guitarist Steve Morse, bassist Roger Glover, drummer Ian Paice, and keyboardist Don Airey (Jon Lord, whose distorted organ parts were so much a part of the classic Deep Purple sound, left the band in 2002 and died in 2012 of pancreatic cancer), one can only marvel at how timeless it sounds, as if it were actually recorded in the early '70s and not tracked a little more than a decade into the 21st century.

No one, least of all Deep Purple themselves, expected the success of 2013's Now What?! It placed at number one on four European album charts and in the Top Ten of six other countries. It also sold exceptionally well: It was certified Gold in Poland, Germany (where it sold over 100,000), the Czech Republic, and Russia – it was the band's first album to crack the U.K.'s Top 40 charts in 20 years. For InFinite, Deep Purple re-enlisted producer Bob Ezrin. At this point, he is almost a sixth member. This the longest running lineup in their history. InFinite is a heavier and more expansive record than its predecessor, but it's not as consistent. Ian Gillian is in excellent form – still possessing intense expressive power and range, his falsetto remains intact four decades on. Don Airey's organ and keys – so elemental in DP's musical architecture – is physical, atmospheric, and dynamic.

Deep Purple's definitive Mark II lineup reunited for 1984's Perfect Strangers. It is one of the better examples of a reunion album, although the band's uneasy camaraderie only lasted a few more years. "Knocking at Your Back Door" opens the album with a roar. Ian Gillan's lyrics don't make much sense, but Ritchie Blackmore's guitar riffs and Ian Paice's thunderous drumming carry this song as well as the rest of the album. The robotic rhythm of the title cut relies on Jon Lord's organ work. The 1999 remastered reissue features the bonus track "Son of Alerik." This fascinating, mid-tempo, ten-minute instrumental was the B-side of the "Perfect Strangers" 12" single in the U.K.

Deep Purple's 2005 album Rapture of the Deep generally maintains the quality of 2003's surprisingly sturdy Bananas. It's the second release from the re-energized lineup of vocalist Ian Gillan, guitarist Steve Morse, bass guitarist Roger Glover, drummer Ian Paice, and keyboardist Don Airey, who replaced the retired Jon Lord. The band's comfort level has increased, and after nearly a decade on board, Morse's stamp is all over the place. At first, this guitar genius' presence was noticeable because of what it lacked – the incredibly distinctive Fender Stratocaster electric guitar tone of Ritchie Blackmore.

After five decades of records made chiefly of original material, Deep Purple’s 22nd studio album consists solely of songs written and previously recorded by other artists: a criminal offense commonly described by the rock police and purists Grand Jury as “doing covers.” Studio recordings of songs previously released by Love, Huey “Piano” Smith, Fleetwood Mac, Mitch Ryder & the Detroit Wheels, Bob Dylan, Ray Charles & Quincy Jones, Little Feat, The Yardbirds, Lonnie Donegan/ Johnny Horton, Bob Seger System, Cream, plus the “Caught In The Act” medley feat. songs by Freddie King, Booker T. and the M.G.’s, The Allman Brothers Band, Led Zeppelin and The Spencer Davis Group came to life with the band, for the first time in their career, recording them while not being in the same room. “Turning To Crime” is Deep Purple enjoying playing music without commercial plans nor losing their edge and drive. This is Deep Purple coming full circle. This is 100% Deep Purple.

This collection of six live songs recorded by Deep Purple at the San Diego Sports Arena in 1974 includes their rock anthem "Smoke on the Water" and a five minute keyboard solo. The album was recorded at the final show of a highly successful American tour, the first to feature new members David Coverdale (Lead vocals) and Glenn Hughes (Bass, vocals) replacing Ian Gillan and Roger Glover respectively, and just 3 days after Deep Purple's legendary performance at the California Jam.