Boris Sergeevich Kuzin (1903-1975), a famous scientist, theoretical biologist, Lamarkist, went down in the history of Russian literature of the 20th century as the closest friend of Osip Mandelstam. The significance of this friendship cannot be overestimated. The poet's words were addressed to Kuzin: When I slept without an appearance and warehouse, I was awakened by friendship, like a shot. God Nachtigal, give me the fate of Pilad Il, tear out my tongue - I don't need it. In this book, B.S. Kuzin appears not only as a deep memoirist and original thinker, but also as a bright prose writer and talented poet. With all certainty, we can say that without taking into account his literary achievements, the picture of Russian literature will be incomplete. His free voice, known only to his closest friends, now reaches through and through the thickness of the past pitch time. The amazing integrity, authenticity and vagueness characteristic of this person seem to illuminate us who read his works today. Miraculously, one hundred and ninety-two letters from Nadezhda Mandelstam addressed to Boris Kuzin survived.