It is doubtless Sarah Thornton's academic credentials - a doctorate in sociology - that persuade her to describe Seven Days in the Art World as an "ethnographic project". But don't be put off. This is an entertaining and lucid account of the mysterious ways of contemporary art. It would have been unthinkable, and certainly unsellable, just 15 or 20 years ago. But we currently live in an extraordinary era for this most curious of cultural phenomena.

Few would have thought that Damien's dots and Tracey's tent would enter the national psyche with the snap and crackle that used to be reserved for catchy pop songs, much less that more than five million spectators would visit an art gallery - Tate Modern - in a single year to pay homage to a giant crack in the ground. Contemporary art is the hottest cultural form around.