Bjork is back after a long time in the laboratory. She has a unique sound that uses progressive dance music with a real eerie sound. ‘Who Is It’ is a real experimental song with lots of effects and layers. She uses her own voice to make unusual sounds in the background while the main vocal track is strong and full of character. She’s a deep lass who certainly stretches the musical boundary. It’s a real grower in the melancholy school of thought however it doesn’t have that seductive soul that Sia creates. A complicated track that has that unique Bjork stamp.