 Clarke was keen in his writing and it is even said that he had a desk in his carriage .For many years, he was the editor of "The Homeopathic World".He wrote many books, his best known were "Dictionary of Practical Materia Medica" and "Repertory of Materia Medica" (i.e., the "Clinical Repertory"), both of which are recommended by the U.S. Food and Drug Administration's rules on "Conditions under Which Homeopathic Drugs May be Marketed".