In this seminal work, Immanuel Kant seeks to identify and establish the supreme principle of morality. He argues that the only thing good without qualification is a 'good will.' Kant introduces the concept of duty and the categorical imperative, a universal moral law that all rational beings must follow, regardless of personal desires or outcomes. This foundational text lays the groundwork for deontological ethics, challenging readers to base morality on pure reason rather than on empirical consequences, and remains a cornerstone of modern philosophical thought.