Henslow's importance as Darwin's mentor is well established. He recommended Darwin for the post of naturalist on the Beagle and also encouraged him to read Lyell's pivotal geology text (also reissued in this series). While professor of botany at Cambridge, Henslow nurtured independent inquiry and acute observation in his students. These attributes are evident in this liberally illustrated 1835 book, which also reveals the influence of Candolle's Théorie Elémentaire de la Botanique (1813) and Physiologie Végétale (1832). Henslow's book, like his meticulous research papers and his innovative lectures, included focussed investigations on the nature and stability of 'species'. Charles Darwin paid such close attention that he became known as 'the man who walks with Henslow', and Henslow's teachings were to echo through Darwin's writings, from his jottings in notebooks on the Beagle onward. This reissue gives modern readers easy access to the work of this inspirational scientist.