Last year was undeniably all about Fever Ray; the world could have been in danger of forgetting The Knife. 2010 sees the return of the siblings Karin Dreijer Andersson and Olof Dreijer on CD, with an opera-concept double album, based around Darwin's "Origin of the Species"... well would you expect anything less? The duo is joined in collaboration with Mt. Sims (Berlin-based American DJ performance artist) and Planningtorock. There are also appearances from Kristina Wahlin Momme, a mezzo-soprano singer, Danish actress Laerke Winther Andersen and Jonathan Johansson, the Swedish pop artist.

The first CD builds slowly – very slowly, taking into account the slow creeping of electronic ticks and tones, before firing off into operatic territory midway through "Epochs". The quality of the music is exemplary, and full of tuneful experimentation; providing the perfect foil for the operatics of Momme. Being that the album is a soundtrack to a production also entitled “Tomorrow, in a Year”, commissioned by the live art troupe Hotel Pro Forma, don't expect it to be full of dancefloor friendly tuneage - the key factor here is experimentation, atmospherically bobbing and weaving through the voices that ghost along through the course of the CD:s.

The easiest way to listen to the album is to turn off the lights and imagine the images that go through your mind while the music unfolds, if you dare. Make no mistake; this CD isn't for the faint-hearted. It is a challenge for even the most open-minded of electronic music connoisseurs: It is longer than 1.5 hours in length, and filled with various clicks, squelches, feedback and noise – it is quite organic too, with little in the way of typical song structure. “Variation of Birds” is notable in this testing of your resolve, being that the span of the track incorporates a howling of industrial electronic noise for well into half its lifespan.

CD two picks up the baton and throws it even further into the ether. Pounding kettle drum noises pummel electronic whooshes across your headphones, and leave you breathless as your imagination goes into overdrive, before suddenly morphing into the noticeably rhythmic almost-song “Colouring of Pigeons” - compelling not just for being something you can actually nod your head to, but being a fine example of a fusion of electronica and opera. The experimentation takes shape into more recognisable beats and pieces, and there is something of a more experimental electronic element to the final third, which is very welcome.

I feel this album will once again separate the purists from the followers – and scare a fair few people along the way. “Seeds” is the nearest people will get to a track they recognise, and can dance to – so for those who like the old Knife groove, they may be left slightly baffled by it all. Some people may be unwilling to pay for a double album where only the last few tracks resemble old work, but for me that defeats the object. From my point of view, there is always room for something as compelling and strange as this album turned out to be. Not for all, but then it's probably better that way too.