It's been one year since Iron Maiden released their 16th album, The Book of Souls, and the remarkably ambitious double album has added another chapter to the band's legacy. The sheer scope of the record  — 12 tracks spanning 92 minutes — and the band’s massive world tour in support of it kept fans busy these past 12 months.

A year later, The Book of Souls is no less impressive than when it first came out. The energy of the album, which was written and recorded quickly at Paris’ Guillaume Tell Studios, roars and pulses like a classic Maiden album. While so many other ’80s metal bands devolve into glorified tribute acts, Maiden remain relevant with music that pushes their old style into bold new territories.

Maybe it’s their advancing age, or maybe it's the five-year pause between Souls and its predecessor, 2010's The Final Frontier,  but is a monumental record in the band's extensive catalog. It’s the first double album they’ve ever released and their longest. It also includes their longest song: the 18-minute closing track “Empire of the Clouds,” which unseated the 14-minute classic “Rime of the Ancient Mariner” after 21 years as the reigning champ.

Despite the voluminous content, there’s a sense of urgency that drives the album, in both music and lyrics. Thematically, the band spends the album’s 90-plus minutes primarily wrestling with issues of life, death and the idea of the immortal soul as triple-threat guitarists Dave Murray, Adrian Smith and Janick Gers shred all over the place. Bassist Steve Harris had gone through an especially difficult period prior to the release, having lost an old friend and family member, and fittingly, it sounds like Maiden are playing like it’s their last day on earth. Another blow came just before the album's release, when singer Bruce Dickinson was treated for oral cancer, prompting a delay of both the album and tour.

Critics were nearly as effusive in their praise of the album as fans were -- with publications like Kerrang! and Metal Hammer awarding the LP with their highest scores. Even the detractors were somewhat tempered in their rebukes, like Billboard, which called The Book of Souls “outsized” but “surprisingly engaging overall.” Ultimate Classic Rock was also impressed by the record's range.

Commercially, the album also fared well. It was the band’s fifth No. 1 in their U.K. homeland, while in the U.S., it debuted at No. 4, Iron Maiden’s highest position along with The Final Frontier. Billboard also noted it was the band’s best sales week in the U.S. since the Nielsen SoundScan tracking system started in 1991.

The world tour was even more successful. Kicking off last February, the road trip found Iron Maiden playing 36 countries across six continents, including their first-ever performances in El Salvador, Lithuania and China. (The El Salvador show was reportedly the largest ever in the nation’s history, earning the group a special thanks from the country's Ministry of Tourism.)

Throughout the tour, the band, crew and more than 12 tons of gear traveled in a custom Boeing 747-400, nicknamed Ed Force One and piloted by Dickinson. Even a March 12 collision on the tarmac in Santiago, Chile — which damaged the plane’s undercarriage and two of its engines, requiring two weeks of repairs — couldn’t derail the momentum. The shows were a hit with both fans and critics. Our sister site, Loudwire, proclaimed Dickinson’s “golden pipes are very much intact.” The tour wrapped up on Aug. 4 at the Wacken Open Air festival in Germany.

For now, it doesn’t appear Iron Maiden are ready to slow down. In recent interviews, Harris said he believes the band will record at least one more album before potentially going on hiatus or breaking up. Dickinson’s cancer scare, as well as the members' advancing ages, seems to have injected new life into a group that could have rested on its past years ago. For Iron Maiden, creativity — and the occasional really long song — is the key to longevity.

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