We don’t really know the material Davis and the band were playing, and it isn’t presented in a way that coincides with our expectations; at the same time, it sounds unlike anything we’ve heard before. We have no frames of reference that are applicable, and are unable to classify the work according to our established taxonomies. We lack not only a map, but also a functioning compass. Therefore we conclude that this is ‘difficult music’, that these forbiddingly long chunks of improperly named, barely navigable, often very abstractly shapeless blocks of sound have been built into walls so high we cannot climb them - so daunting and monolithic we can only stand awestruck in their presence before retreating to the comforts and securities of three-minute songs with recognisable hooks and names that relate to the images the tunes conjure or the lyrics a vocalist weaves in and around the tune.