Here is a slim, beautifully-produced volume aimed, I think, at the well-educated browser. Its essence lies in the charm of disinterest. Rousseau’s definition of botany as a study of pure curiosity has been incorporated into the present title from the seventh of eight letters originally published at Lettres Elémentaires sur la Botanique. In his introduction Roy McMullen doubts that Rousseau wanted to discount the scientific value of a subject that at times claimed all his intellectual resources. But he rightly alerts the reader to the tone of ‘gentlemanly amateurism’ that colours this minor work of the last years. That is its modern appeal.