"How the Steel Was Tempered" (Russian: Как закалялась сталь) is a novel written by the Soviet writer Nikolai Ostrovsky, written in 1933. The most well-known sentence in the book is "The most precious thing in life is life. Life is only once for people. A person's life should be spent like this: when he looks back on the past, he will not regret for wasting his years; nor will he regret it. Shame on me for doing nothing.

When he was dying, he could say: My whole life and all my energy have been dedicated to the most magnificent cause in the world - the struggle for the liberation of mankind! "The English translation of this sentence is as follows:

"Man's dearest possession is life. It is given to him but once, and he must live it so as to feel no torturing regrets for wasted years, never know the burning shame of a mean and petty past; so live that, dying, he might say: all my life, all my strength were given to the finest cause in all the world──the fight for the Liberation of Mankind”

― Nikolai Ostrovsky