Christchurch people would have felt a jolt of recognition at Matias Faldbakken’s contribution to Documenta. Hidden away in the back of the Kassel Public Library the Danish artist had pulled out the books in the Self Help section and left them on the floor where they fell. Perhaps it is a “cannily coded discourse on loss and catastrophe” as the catalogue has it or maybe, more realistically, just something people could do without happening again.