Among the Telegraph's picks is the extraordinary "Vincent van Gogh: the Letters: the Complete, Illustrated and Annotated Edition" (www.vangoghletters.org), the inspiring product of 15 years’ research, and Martin Gayford’s "Constable in Love," a romantic account of the muse behind the artist’s familiar landscapes. In "Sleuth," art dealer and Antiques Roadshow expert Philip Mould argues persuasively that the thrilling “discovery” of a great master is still possible in our technologically joined-up world.