The Book of Souls is the sixteenth studio album by English heavy metal band Iron Maiden, released on 4 September 2015.

Its launch and supporting tour were delayed to allow vocalist Bruce Dickinson time to recover from the removal of a cancerous tumour in early 2015.

Produced by long-time Iron Maiden collaborator Kevin Shirley, The Book of Souls was recorded at Guillaume Tell Studios, Paris from September to December 2014, which they had previously used for 2000's Brave New World.

While not a concept album, references to the soul and mortality are prominent, realised in the Maya-themed cover artwork, created by Mark Wilkinson.

[3] The album was recorded at Guillaume Tell Studios, Paris with producer Kevin Shirley from September to December 2014,[4] with the finishing touches added in early 2015.

"[6] The band originally intended to release the record earlier in 2015, but it was pushed back to 4 September while Dickinson received treatment for a cancerous tumour.

[15] The artwork was created by Mark Wilkinson,[5] whose previous works for Iron Maiden include Live at Donington (1998 remastered version) and Best of the 'B' Sides (2002 compilation), as well as "The Wicker Man" and "Out of the Silent Planet" singles covers.

[16] According to bassist Steve Harris, the cover art ties in with the title track, as the depiction of the band's mascot, Eddie, is based on the Maya civilization, who "believe that souls live on [after death]".

[20] The Book of Souls World Tour began in February with the band performing in 35 countries across North and South America, Asia, Australasia, Africa and Europe.

[25] With both tracks, Smith and Dickinson deliberately wrote shorter songs in an attempt to hark back to previous singles "2 Minutes to Midnight" (1984) and "Can I Play with Madness" (1988).

[19] Unlike the band's previous two albums, 2006's A Matter of Life and Death and 2010's The Final Frontier, Harris does not receive a writing credit for all of the record's songs.

[19] One of Harris' contributions, "Tears of a Clown", which he co-wrote with Smith, is praised by Dickinson as his favourite track from The Book of Souls and is based on comedian Robin Williams' depression and suicide in 2014.

[23] According to Smith, Dickinson spent most of the album's recording sessions alone writing the song in a "soundproof glass box with his piano",[22] which he completed with assistance from McBrain.

and Metal Hammer gave it full marks: the former labelling it "an album of extraordinary vision";[35] the latter "a gargantuan emotional journey through some career-best performances that more than makes up for a five-year wait".

"[31] The Guardian also scored it 4 out of 5 and, despite criticising the "lumbering 'Shadows of the Valley'", exclaimed that "The Book of Souls is marked by an impressive rawness that scratches against the album's more grandiloquent moments".

[31] Although Blabbermouth.net and NME did not agree that it matches "Rime of the Ancient Mariner", the former stated that it is "worth every single minute as a cinematic-sounding encapsulation of the band's career",[41] while the latter called it "the pièce-de-résistance".

[32] Sputnikmusic rated it "a significant improvement" on the closing tracks from the band's two previous studio records ("The Legacy" from 2006's A Matter of Life and Death and "When the Wild Wind Blows" from 2010's The Final Frontier), calling it "cerebral and evocative".

[34] The Guardian complimented the 13-and-a-half-minute "The Red and the Black" for its "genuine urgency and agility",[34] while PopMatters dubbed it "as predictable as [Harris's] songwriting gets, [but] this time around it's a delight to hear".