After moving to London, Stearn produced a steady output of publications during his years at the Royal Horticultural Society's Lindley Library (1933–1952). These covered a wide range of topics from bibliography to plant nomenclature, taxonomy and garden plants, with a particular emphasis on "Vinca", "Epimedium" and "Lilium". Within two years of joining the library in 1933, he had produced his first major monograph, "Lilies" (1935), in collaboration with Drysdale Woodcock and John Coutts. This text, in an expanded and revised edition, as Woodcock and Stearn's "Lilies of the World" (1950) became a standard work on the Liliaceae "sensu lato". While at the library he also continued his collaboration with his Cambridge colleagues, publishing catalogues of the Herbarium collections, including the "Catalogue of the Collections of the Herbarium of the University Botany School, Cambridge" (1935). The second task imposed on him at this time involved the RHS role in maintaining revision of the Code of Botanical Nomenclature ("see" Botanical taxonomy).