A fascinating exercise and assay, Traces of Vermeer (Oxford, $34.95) serves as an elucidating technical accompaniment to the broader scope of Vermeer in Detail. Jane Jelley is, first and foremost, a painter. But she has become something of a reconstructive art historian through her engagement with Vermeer and his artistic process. Vermeer’s startling command of light, the snapshot-like quality of his 17^th century masterworks, has long baffled even his greatest admirers. It would seem he used a camera obscura as an optic aide, but how exactly Vermeer might have used it—and whether its use in some way detracts from his genius—has been highly controversial. Jelley brings a vast knowledge, and, more importantly, practice, of traditional painting techniques to this discussion: grinding one’s own pigment, preparing canvases, long apprenticeships, third glazes. Through trials in the studio, she proposes a novel suggestion as to how exactly Vermeer could have used a camera obscura lens to arrive at his compositions, plot them onto canvas, and then prepare and layer paint to create his unparalleled works. The process, she maintains, would only further elevate Vermeer’s genius. Jelley’s engaging prose is a boon to both scholars and casual art appreciators.