Rousseau published his Lettres Elementaires Sur La Botanique in 1771-73. This work contains eight letters teaching a young mother about botany and how to study it so she can teach the subject to her daughter. Rousseau addressed the work to Madame Delessert, the mother of the French financier Benjamin Delessert, 1773-1847, who was a keen botanist and the owner of a famous herbarium and botanical library. Botany was a favorite amusement of Rousseau’s in later life. Thomas Martyn, a professor of botany at Cambridge and one of the earliest exponents of Linnaean classification, translated Rousseau’s work into English in 1785. He added 24 letters of his own on the subject in the edition shown here. Over the next 30 years there were eight editions of Martyn’s work; it was a very influential, popular work on botany. A lady should be able to identify plants herself!