"Criticism of practical reason" is a main ethic treatise of Иммануила of Канта, developing the ideas of his "Criticism of clean reason" and in detail investigating the concept of categorical imperative, - higher principle of morality. According to statement of philosopher, a man can be truly happy, only if realizes that deserve happiness. And it can be attained, only discharging duty, id est following a moral law. On Канту, acting so a man, regardless of external circumstances, perceptible necessities and other motives, becomes truly free.One of leading translators of Канта into Russian language was a poet, literary critic and critic Nikolay Матвеевич Соколов (1860-1908). Translating the basic treatises of Канта, later he presented to the Russian readers and other his works. Translations of Соколова are considered exact and complete, they repeatedly reprinted in soviet time.As well as other books of series the "Great ideas", a book will be simply irreplaceable in the library of students of humanitarian specialities, and also for persons interested to become acquainted with key works and ideas of world philosophy and culture.In the format of a4.pdf is stored publishing layout.