We've heard the new Nightwish album, and as it's amazing, we thought we'd present to you are track-by-track guide.

Nightwish's sixth album, and their first for four years, is a 75 minute epic that covers far more territory than can be summed up briefly. So that's why we have our track-by-track guide to 'Imaginaerum' (released on December 5) in full, and without further ado...

'Taikatalvi'

An intro track of sorts, the album opens with chiming percussion and soft male vocals under which the instrumentals swell, more and more elements coming into play that becomes a surging, choral climax into 'Storytime'.

'Storytime'

Immediately storming into much faster, heavier and darker territories, this is, even before Anette Olzon's vocals come in, consummate Nightwish- driving, epic and richly layered with deep brass tones and sweeping strings. Later, it falls away into wordless choir and piano before the drums and guitars return before the massed choir enters. It's one of the most grandiose, atmospheric and sumptuous sequences of music Nightwish have put their name to.

'Ghost River'

Another heavy track that retains its richness through the heft, this is all dreamy melodies in the symphony and swung rhythms in the vocals which feature some beautiful interplay between Marco Hietala and Anette, before a huge orchestral break leads into crunching riffage. It's at this point it starts to become clear that the more predictable song structures of 'Dark Passion Play' have been left way, way behind and have been replaced by much more interesting, evocative composition.

'Slow, Love, Slow'

A husky, sexy and sultry jazz number (yes, jazz) with some fantastic, delicate drumming and an extraordinary vocal performance from Anette, who showcases an entirely new aspect to her abilities. Later, a fusion solo is followed by ethereal orchestrations as the metallic darkness returns, only to fade as a Louie Armstrong trumpet solo plays out over a ticking clock, rounding off a moment the like of which has never been heard from Nightwish before.

'I Want My Tears Back'

One of the very few straight-up verse-chorus-verse structured songs, this is all the stronger for standing out so clearly- it's big, bombastic, full of hooks and swaggering with riffage as Celtic melodies swirl around, and sounds like one the crowds will know backwards by the time Nightwish come to tour. The density of ideas is still there in force, but it's one of the more accessible numbers on an album with wonderfully too much going to take in at one sitting.

'Scaretale'

A children's choir leads into an ascending, staccato orchestral depth as the young voices are replaced by mature choral power on this racing, turbulent journey that features some sinister vocal inflections before a circus-style march emerges in a style all of Nightwish's own. The absolutely vast choir, orchestra and guitars all return in force before fairground music ends the piece.

'Arabesque'

A sweeping instrumental odyssey that once again sound enormous and genuinely epic, like the score to a gigantic adventure in the East complete with seductive dance rhythms and massive percussion, that ends suddenly and dramatically.

'Turn Loose The Mermaids'

The start of a triad of softer songs, 'Turn Loose The Mermaid' is all acoustic guitars and soft strings that rise gently but with huge emotion. Anette's performance on vocals is once more superb, needing to carry much of the weight of the track as the instrumentals become more subtle in pipes and piano parts.

'Rest Calm'

Initially sounding slightly like one of Rammstein's slower numbers – 'Mutter', for example – 'Rest Calm' is at it's heart beautifully soothing and tranquil, but achieves this by first storming to highlight the placid centres in between the chug.

'The Crow, The Owl And The Dove'

Acoustic guitars lilt beneath a superb duet between Marco and Anette, before Marco drops away and and the strings swell beneath the frontwoman, only for the soft vocal interplay to return. Folky sounds lead into more metal territory that falls back for the last time to piano and crooning.

'Last Ride Of The Day'

The album's second simple track, this is classic Nightwish at their catchiest- rise and fall, hard and soft, crunching and luscious... it's big and pumping and sequentially if not texturally instantly comprehensible, and leads into the album's climax.

'Song Of Myself'

A four-part epic that starts with a huge orchestral attack in colossal, Danny Elfman-esque drama and sets out purposefully through the myriad of moods that between them almost surmise everything that Nightwish do best in one single track- metallic weight and pace balanced with lyrical slowness, vast, melancholy sounds of true beauty, and the moving spoken poetry in the last section brings to an end one of the most heroic achievements of the band's career.

'Imaginaerum'

An orchestral summation of the whole album, in effect- the huge massed wind, brass, strings and percussion recapitulate some of the highlights from the whole album, wonderfully weaving a final bow on the whole parcel.

The step up in strength from the last album is quite spectacular. All involved put in stellar performances, and Tarja is now decidedly not missed- Nightwish have come too far from that era, and are something different and astonishing. 'Imaginaerum' offers a vast depth of utterly splendid music.