For forty-three years of my conscious life I have remained a revolutionist; for forty-two of them I have fought under the banner of Marxism. If I had to begin all over again I would of course try to avoid this or that mistake, but the main course of my life would remain unchanged. I shall die a proletarian revolutionist, a Marxist, a dialectical materialist, and, consequently, an irreconcilable atheist. My faith in the communist future of mankind is not less ardent, indeed it is firmer today, than it was in the days of my youth.

Trotsky's Testament (1940)