By Adam Easton
BBC News, Warsaw
Leszek Kolakowski was regarded as a leading anti-totalitarian writer
The Polish philosopher and historian of ideas, Leszek Kolakowski has died in hospital in Oxford, England. He was 81.
One of the few 20th Century eastern European thinkers to gain international renown, he spent almost half of his life in exile from his native country.
He argued that the cruelties of Stalinism were not an aberration, but the logical conclusion of Marxism.
MPs in Warsaw observed a minute's silence to remember his contribution to a free and democratic Poland.
Leszek Kolakowski was born in Radom, Poland, 12 years before the outbreak of the World War II.
Under the Nazi occupation of Poland school classes were banned so he taught himself foreign languages and literature.
He even systematically read through an incomplete encyclopaedia he found.
He once said he knew everything under the letters, A, D and E, but nothing about the Bs and the Cs.
After the war he studied philosophy and became a professor. Seeing the destruction wrought by the Nazis in Poland he joined the Communist Party.
But he gradually became disillusioned and more daring in his criticism of the system. In 1966 he was expelled from the party and two years later he lost his job.
Seeking exile in the West, he eventually settled at Oxford's All Souls college where he wrote his best-known work, the three-volume Main Currents of Marxism, considered by some to be one of the most important books on political theory of the 20th Century.
In the 1980s, from his base in Britain, he supported Poland's pro-democracy Solidarity movement which overthrew communism in 1989.
For many of its leaders he was an icon.