KRAKOW, Poland (Reuters) - Polish author Stanislaw Lem, one of the world's leading science-fiction writers, died on Monday in his home city of Krakow at the age of 84 after a battle with heart disease.

Lem, whose books have sold more than 27 million copies and have been translated into more than 40 languages, won widespread acclaim for The Cyberiad, stories from a mechanical world ruled by robots, first published in English in 1974.

Solaris, published in 1961 and set on an isolated space stations, was made into a film epic 10 years later by Russian director Andrei Tarkovsky and into a 2002 Hollywood remake shot by Steven Sodebergh and starring George Clooney.

"Shortly after 3 p.m. (1300 GMT) Stanislaw Lem died in the heart clinic, where he had been treated over the past few weeks for circulatory problems," Andrzej Kulig, director of the Jagiellonian University hospital told Reuters.

Lem, born on September 12, 1921 in what is now the Ukrainian city of Lviv, studied medicine before World War Two. After the war, communist censorship blocked the publication of his earliest writing.

After the fall of communism in 1989 Lem ceased writing science-fiction, instead devoting himself to reports on near-future predictions for governments and organizations.

He wrote essays on computer crime, as well as technological and ethical problems posed by the expansion of the Internet.