I only discovered this by reading Sue Hubbard's beautiful short story collection Rothko's Red; I am very glad I did. It is excellent, the best art criticism I have come across since Robert Hughes'.
Hubbard writes with insight as well as interest, and her range is huge. Her essays on Rothko, Lucian Freud, Prunella Clough, the Boyle Family are penetrating and informative, but there are so many here, some unknown to me.
It's also a delight to read, stylish and clear, free from the Theory-laden obfuscations of most academic art criticism, which has gone the way of Literary Criticism (it is hard to take seriously an aesthetic judgement from someone incapable of writing a single elegant sentence).
Hubbard is a poet and it shows, not only in her crisp style but also in her range of references, and in her ways of looking - concentrating on the works, not the theoretical grid.
For anyone like me, with a serious but entirely lay interest in contemporary art, and wanting help negotiating the current art world, this would be the perfect guidebook.