In 1976 Daniel Gajdusek received a Nobel Prize in Physiology or Medicine for his work in the 1950s and 60s discovering, identifying and subsequently eradicating a debilitating neurological disease known as kuru. The disease was endemic among members of a Papua New Guinea tribe known as the Fore people, who engaged in the ritualistic consumption of their recently deceased - unknowingly passing on a rogue protein known as a prion, which was responsible for the paralyzation and dementia suffered by those afflicted with kuru.

Diseases caused by prions, which includes mad cow disease in animals and its human brother Creutzfeldt-Jakob disease, are completely untreatable and always fatal. When Gajdusek put a halt on the Fore people's cannibalistic practice of consuming the brains of dead people, the disease was completely eradicated within a generation. Humans normally have a natural genetic defence against kuru and other prion-caused diseases, suggesting that cannibalism has been so prevalent in human history that we actually evolved a gene to protect against it.

What's this got to do with anything? Well, Kuru is the title and one theme of the new album from Mushroom Giant, a prolific group of Melburnian instrumental rockers. A strange theme for an album, certainly, made stranger by the fact that the record is completely devoid of lyrics - meaning the only way anyone would know that it's about cannibalism, evolution, death or rebirth is by reading the short blurb inside the album that tells Gajdusek's story.

In similar fashion to Sigur Ros' seminal post-rock album ( ), the sparsity of the album's artwork encourages the listener to insert their own meaning into the music. The closest one gets to an explanation of the album's subject matter apart from the vague cannibalism-themed blurb is a single subtitle for each song, and a collection of quotes from historical figures such as Albert Einstein or the artist Edvard Munch. Everything else is up to you.

But once you get past its creepy subject matter and the foreboding artwork that envelopes the CD, the music contained within it has much the same beauty and dignity as death itself.

Mushroom Giant have been quietly perfecting their art over the past five years, and their proficiency is evident on Kuru. Evoking comparisons to Godspeed You! Black Emperor and Mono - bands who often teeter on the edge of out-and-out metal but also have a quieter, subtle side - Kuru is a rollercoaster ride from start to end.

In the album opener "Graven Image", one of post-rock's signature techniques is employed: gradually threading a melody into a repetitive rhythm, building closer and closer towards a crescendo. The difference here is in the upbeat, pounding drumbeat that drives the song at a speedy pace, making the song more dance-rock than post-rock. A crushing, distorted guitar effect in the final 20 seconds of the track offers one of many headbanging opportunities to come for those so inclined.

Putting a subtle spin on tried and true musical techniques is one of the album's hallmarks.

"Autumn Leaves The Dead", awash in the soothing sound of a violin, is decidedly more laid back in mood than its predecessor. Its subtitle, "Shedding Skin", evokes images of a transformation or rebirth, and that is exactly the mood projected by the song. "Sirenthia" is similar, though the violin is much higher in the mix, much more angular, much more off-key, turning the usually pleasant-sounding instrument into something much more uncomfortable to hear. The contrast between pleasant and unpleasant is perhaps an exploration of the dignity of natural death and the indignity of murder, although the listener is once again left to place their own meaning in the music.

The theme of death is revisited later in the song "Poor Tom", subtitled "Murder Scene". Simply harrowing to listen to, merely two minutes long but so perfectly projecting the mood of a violent murder that it would be quite at home on any serial killer movie score. Schitzophrenic in mood, it breathes in and out between pounding, rapid-fire heaviness and near silence, as if telling the story of a killer who blanks out with rage one minute and is totally calm the next, with no recollection of what had happened seconds prior.

This is what Mushroom Giant do best: project moods, paint scenes and tell stories, all purely using music, and without any lyrics. This is a rare skill.

Kuru is a truly deep album, one not easily judged after a single listen, but one that becomes more rewarding with each listen. Give it the time and space it needs to show itself to you, and the album's beauty will make itself evident.

If you buy this album, and I suggest anyone with an interest in post-rock or progressive metal should do so, when you bring it home you should close the door, turn out the light, turn up your stereo and let your mind wander. Kuru will take you places.

Check Mushroom Giant out at their website www.mushroomgiant.com or listen to more of their tunes on their MySpace page: www.myspace.com/mushroomgiant.