He is best known for his critical analyses of Marxist thought, especially his three-volume history, Main Currents of Marxism (1976). In his later work, Kolakowski increasingly focused on religious questions. In his 1986 Jefferson Lecture, he asserted that "We learn history not in order to know how to behave or how to succeed, but to know who we are."
Kołakowski was born in Radom, Poland. He did not enjoy formal schooling during the German occupation of Poland (1939–1945) in World War II, but did read books and took occasional private lessons, passing his school-leaving examinations as an external student in the undergroundschool system. After the war he studied philosophy at Łódź University. By the late 1940s it was obvious that he was one of the most brilliant Polish minds of his generation, and in 1953 earned a doctorate from Warsaw University with a thesis on Baruch Spinoza in which he viewed Spinoza from a Marxist point of view. He served as a professor and chairman of Warsaw University's department of the history of philosophy from 1959 to 1968.
He came to the conclusion that the totalitarian cruelty of Stalinism was not an aberration, but instead a logical end-product of Marxism, whose genealogy he examined in his monumental Main Currents of Marxism, his major work, published in 1976–1978.
Kolakowski became increasingly fascinated by the contribution which theological assumptions make to Western, and, in particular, modern thought. For example, he begins his Main Currents of Marxism with an analysis of the contribution that various forms of mediaeval Platonism made, centuries later, to the Hegelian view of history. In this work he criticized the laws of dialectical materialism for being fundamentally flawed— finding some of them being "truisms with no specific Marxist content", others "philosophical dogmas that cannot be proved by scientific means", yet others being just "nonsense".
His Law of the Infinite Cornucopia asserts a doctrine of status quaestionis - that for any given doctrine one wants to believe, there is never a shortage of arguments by which one can support it. Nevertheless, although human fallibility implies that we ought to treat claims to infallibility with scepticism, our pursuit of the higher (such as truth and goodness) is ennobling.
Although the Polish Communist authorities officially banned his works in Poland, underground copies of them influenced the opinions of the Polish intellectual opposition. His 1971 essay Theses on Hope and Hopelessness (full title : In Stalin's Countries: Theses on Hope and Despair), which suggested that self-organized social groups could gradually expand the spheres of civil society in a totalitarian state, helped to inspire the dissident movements of the 1970s that led to Solidarity and, eventually, to the collapse of Communist rule in Europe in 1989. In the 1980s, Kołakowski supported Solidarity by giving interviews, writing and fund-raising.
Kołakowski died on 17 July 2009, aged 81, in Oxford, England. In his obituary, philosopher Roger Scruton said Kolakowski was a "thinker for our time" and that regarding Kolakowski's debates with intellectual opponents, "even if ... nothing remained of the subversive orthodoxies, nobody felt damaged in their ego or defeated in their life's project, by arguments which from any other source would have inspired the greatest indignation."
Klucz niebieski, albo opowieści budujące z historii świętej zebrane ku pouczeniu i przestrodze (The Key to Heaven), 1957
Jednostka i nieskończoność. Wolność i antynomie wolności w filozofii Spinozy (The Individual and the Infinite: Freedom and Antinomies of Freedom in Spinoza's Philosophy), 1958
13 bajek z królestwa Lailonii dla dużych i małych (Tales from the Kingdom of Lailonia and the Key to Heaven), 1963. English edition: Hardcover: University of Chicago Press (October 1989). ISBN978-0-226-45039-1.
Rozmowy z diabłem (US title: Conversations with the Devil / UK title: Talk of the Devil; reissued with The Key to Heaven under the title The Devil and Scripture, 1973), 1965
Świadomość religijna i więź kościelna, 1965
Od Hume'a do Koła Wiedeńskiego (the 1st edition:The Alienation of Reason, translated by Norbert Guterman, 1966/ later as Positivist Philosophy from Hume to the Vienna Circle),
Kultura i fetysze (Toward a Marxist Humanism, translated by Jane Zielonko Peel, and Marxism and Beyond), 1967
A Leszek Kołakowski Reader, 1971
Positivist Philosophy, 1971
TriQuartely 22, 1971
Obecność mitu (The Presence of Myth), 1972. English edition: Paperback: University of Chicago Press (January 1989). ISBN978-0-226-45041-4.
ed. The Socialist Idea, 1974 (with Stuart Hampshire)
Husserl and the Search for Certitude, 1975
Główne nurty marksizmu. First published in Polish (3 volumes) as "Główne nurty marksizmu" (Paris: Instytut Literacki, 1976) and in English (3 volumes) as "Main Currents of Marxism" (London: Oxford University Press, 1978). Current editions: Paperback (1 volume): W. W. Norton & Company (17 January 2008). ISBN978-0393329438. Hardcover (1 volume): W. W. Norton & Company; First edition (7 November 2005). ISBN978-0393060546.
Czy diabeł może być zbawiony i 27 innych kazań, 1982
Religion: If There Is No God, 1982
Le Village introuvable, 1986
Metaphysical Horror, 1988. Revised edition: Paperback: University of Chicago Press (July 2001). ISBN978-0-226-45055-1.
Pochwała niekonsekwencji, 1989 (ed. by Zbigniew Menzel)
Cywilizacja na ławie oskarżonych, 1990 (ed. by Paweł Kłoczowski)
God Owes Us Nothing: A Brief Remark on Pascal's Religion and on the Spirit of Jansenism, 1995. Paperback: University of Chicago Press (May 1998). ISBN978-0-226-45053-7. Hardcover: University of Chicago Press (November 1995). ISBN978-0-226-45051-3.
Freedom, Fame, Lying, and Betrayal: Essays on Everyday Life, 1999
The Two Eyes of Spinoza and Other Essays on Philosophers, 2004
My Correct Views on Everything, 2005
Why Is There Something Rather Than Nothing?, 2007
Is God Happy?: Selected Essays, 2012
Jezus ośmieszony. Esej apologetyczny i sceptyczny, 2014
^Martin Jay, Marxism and Totality: The Adventures of a Concept from Lukács to Habermas, University of California Press, 1984, p. 5: "Although such thinkers as the Polish philosopher Leszek Kolakowski (during his Marxist Humanist phase) and the Czech philosopher Karel Kosík were certainly important in their own right, their work was nonetheless built upon the earlier thought of Western Marxists, as was that of the Yugoslav theoreticians published in the journal Praxis."