In 1921 Smith wrote the illustrated Handbook of British Lichens which was a key to all known British lichens. In the same year Lichens was published and was quickly established as a classic text.
In 1921 Smith authored "Handbook of British Lichens," a comprehensive guide to all known British lichen species, which quickly became a standard text. The same year saw the publication of "Lichens" and its rapid adoption as a foundational work.