Maria Ossowska, an outstanding Polish theorist of morality conceived of ethics as a science of morals. The author underscores the characteristic traits of her style of work and surveys her findings in sociology of morals. Maria Ossowska is depicted as a scholar who cautiously formulates and verifies her hypotheses, critically examines her findings and displays indefatigable inquisitiveness, never benefiting from an occasion to explain the facts away with the help of a single kind of factors solely.