The "Critique of Practical Reason" is a philosophical work by Immanuel Kant, published in 1788. It focuses on moral philosophy and explores the nature of human reason in relation to ethics. Kant argues that practical reason is essential for understanding moral law and emphasizes the importance of duty and the categorical imperative, which guides moral actions. In this work, Kant distinguishes between theoretical and practical reason, asserting that while theoretical reason deals with knowledge, practical reason is concerned with action and morality. He aims to establish a foundation for moral principles that are universally applicable, emphasizing autonomy and the role of rationality in ethical decision-making.