It started - as it often does - with a record. A snippet of music and a code that would begin one of the most surprising album campaigns in recent years. When the dots were joined, and the fourth album from Scottish duo Boards of Canada was revealed as Tomorrow's Harvest, expectation shot through the roof; when the atmospheric and ominous lead single 'Reach For the Dead' followed, there was a mixture of shock and awe - after all, one can see how those first few listens could have slipped by in a haze of incredulity: 'wow, this is really happening'. Fast forward another couple of weeks, and the anticipation of the record's crashed the band's website and, supposedly, broke Twitter. For an act so widely regarded as having achieved cult status, and even with the seven-year gap since the Trans-Canada Highway EP, the levels of hype have been impressive. However, all of this begs the question: is Tomorrow's Harvest actually any good?

The answer is a resounding yes. Overall, the album has a cinematic feel that is evident as soon as the unexpected fanfare that opens the record is heard. It unfolds like the soundtrack to some sort of dystopian future, an idea which is reflected in the cover's blurred image of the San Franciscan skyline, and the title of the album itself. Tomorrow's harvest: We have the image of a ghostly city, and the post-apocalyptic feel of much of the album's music only seems to reinforce the idea of it soundtracking the aftermath of some unknown catastrophe. The music on offer is often dark and full of ominous portents - 'White Cylosa' is held together by a brooding D minor chord, its sparse melody lines underpinned by synth arpeggios and distant washes of noise; 'Telepath', meanwhile, breaks up the first half of the album by setting a four-note motif against a seriously unsettling sampled voice, its borderline peaceful feeling given a good shot of fear and dread by the darkness that surrounds it.

'Collapse' is the track around which everything on the record hinges, its unusual rhythm and minimalistic feel causing the darkness of the earlier tracks to be deepened considerably. The album doesn't start out in a particularly welcoming place, with the buzzing drone of 'Gemini' setting the scene and introducing us to Boards of Canada's new sound - when I say 'new', I mean that they haven't broadened their horizons too much, but have improved on certain aspects of what's gone before - but there are times when it feels particularly harrowing; for example, 'Sick Times' is every bit as hesitant and inward-looking as its title would suggest. However, coming out the other side of 'Collapse' reveals arguably the most immediate moment on the album; 'Palace Posy' revolves around a bouncy, major-key synth line and prominent rhythms, and there are other times, such as on 'Nothing is Real' and the particularly impressive 'Split Your Infinities' that positivity starts to seep through. It even seems as though the album will end on an even moderately hopeful note, with the penultimate track 'Come to Dust' given a lightness of touch by its percussive heft and swirling, energetic countermelodies. (There's even a reprise of a motif from 'Reach For the Dead' in there).

All this is, however, is simply a false dawn: the haunting closer 'Semena Mertvykh' strips everything else away to reveal the stark, desolate landscape at the heart of Tomorrow's Harvest, and as it fades away, so does the listener's last hope of the album ending on a positive note. Things don't get much bleaker than this; the whole aesthetic of the record seems to suggest that we're all going to hell in a handbasket. It's music for the end times, and has its full effect when listened to in a dark room with the lights off, and given full focus. It's also an extremely well-constructed record that, at 17 tracks and 62 minutes in length, may seem like a daunting prospect, and you may emerge from listening to it in a rather more contemplative mood than you went into it with, but for an album of this length to feel so intense and utterly engaging throughout is an impressive achievement. It needs to be listened to in the right sort of atmosphere to reach its full effect, but Boards of Canada's return after seven long years and proved it was worth the wait. No matter how you listen to it, Tomorrow's Harvest is astonishing.