Final answer:
Henry Havelock Ellis was a British physician and writer who made pioneering contributions to sexology, particularly with his influential work, 'Studies in the Psychology of Sex'.
Step-by-step explanation:
Henry Havelock Ellis was a British physician, writer, and social reformer who made significant contributions to the field of sexology and human sexuality studies. Among his major works is the seven-volume Studies in the Psychology of Sex, which covers various aspects of sexual psychology and behavior, and helped to lay the foundation for more modern attitudes towards human sexuality. Ellis was a pioneer in his field, breaking many taboos related to sex in the Victorian era. Despite the controversial nature of his work, Ellis influenced several subsequent studies, including those by Alfred Kinsey, whose Sexual Behavior in the Human Male became one of the best-selling and most influential academic publications in the 20th century.