Being and Duty is comprised of three components that: a) analyze the creative contribution to the theory of imperatives and norms provided by 20th-century Polish researchers; b) summarize their reflections and considerations; and c) offer a collection of the classic writings of Polish authors of the time, illustrating that their research covered practically the whole scope of the theory of imperatives and norms. Contents include: the preferential situation * preferences and impulses * decisions and tendencies * the verbalization of preferences - imperatives * the axiological situation - evaluations * the obligational situation * the genesis of the obligation * criteria of factuality of obligation * the gradation of obligations * the verbalization of obligations - norms * norms and consultatives * instructions and optatives * the imperative-normative argumentation.