Doris Lessing, the Nobel prize-winning, free-thinking, world-traveling and often-polarizing author of "The Golden Notebook" and dozens of other novels that reflected her own improbable journey across the former British empire, has died. She was 94.

Her publisher, HarperCollins says that the author of more than 50 works of fiction, nonfiction and poetry, died peacefully early Sunday.

Lessing explored topics ranging from colonial Africa to dystopian Britain, from the mystery of being female to the unknown worlds of science fiction.

She won the Nobel Literature prize in 2007. The Swedish Academy praised Lessing for her "skepticism, fire and visionary power."