Anyone who has listened to Bjork beyond the "chart-friendly" early days of 'Debut' will know to expect the unexpected with each new album. Continuing the introspective feel of 'Verspertine', Medulla (meaning 'bone marrow') will astound and confound most listeners. Eschewing "real instruments" for vocal sounds only (with a little help from a programmer on some tracks) Medulla demands that you listen closely - this isn't background muzak to soothe you after a tired day! Having said that, several tracks are intimately beautiful and are calming and soothing - check out the beautiful choral work of 'Vokuro' or the tingling gentleness of 'Desired Constellation'. At the other end of the spectrum 'Where is the line' is hard, dark and cutting, the human beatbox rhythms driving the incessant lyric forward despite itself. In the middle are melodic but rhythmic songs like 'Oceania' and 'Pleasure is all mine', overlaid with choral vocals that swoop around Bjork's own distinctive voice, as strong as ever. More abstract work such as Sonnets/Unrealities, Ancestors, Oll Birtan can meander a little - they feel like they're unravelled to the point of losing the plot and are the most difficult tracks to get into, but with repeat listening grow and become characteristic in their own ways; Oll Birtan starts to sound like 'Row Row Row your boat' with a simplicity belying its original confrontational style. The outstanding track for me is Mouths Cradle, combining beat, choral voices, programming and a climactic ending that is hard to beat. Overall Medulla contains more beautiful, essential Bjork tracks, continuing her excellent work from earlier albums - not as passionate as 'Homogenic' or as warm and inviting as 'Vespertine' or as startling as 'Debut', 'Medulla' is true to itself, charting the dark inner territories of the human.