This is a rather disappointing collections of essays, particularly coming from the 'Cambridge Companion' stable. The weakest section is the one which provides overviews of various aspects of Dylan's career; there is a lot of repetition, with each writer compelled to tell us yet again what album was recorded when. The best essays are those which focus in depth on particular albums, with Jonathan Letham and Eric Lott particularly perceptive about Infidels and "Love and Theft" respectively. There is also a glaring omission - nothing about Dylan's paintings and drawings.
I think it was Simon Armitage who described writing about music as being like trying to dance about architecture - and this is a book that brings the point home.