STOCKHOLM, Sweden -- Swedish poet and Nobel Literature Prize winner Tomas Transtromer has died at age 83, Swedish publisher Bonniers said Friday.

The reclusive, mild-mannered wordsmith -- considered a master of metaphor and one of the most important Scandinavian poets of the post-World War II era -- died Thursday after a short illness said Bonniers spokeswoman Anna Tillgren.

In famous collections such as the 1966 "Windows and Stones," Transtromer used imaginative metaphors to describe the mysteries of the human mind. His work has been translated into more than 60 languages and influenced poets across Europe, the Middle East and the Americas. In 2011 he was awarded the Nobel Prize in Literature.

Transtromer's works were characterized by powerful imagery that explored the mysterious sides of everyday life with little embellishment, and the focus on simplicity was also mirrored in the way he led his life.

Working as a psychologist in Swedish state institutions, Transtromer (TRAWN-stroh-mur) wrote his poetry during evenings and weekends and stood out for his unpretentious demeanour. He preferred to stay away from the public eye and largely avoided the political debates that engaged many of his contemporaries.

The poet stopped writing after suffering a stroke in 1990 that left him half-paralyzed and largely unable to speak. When he received the Nobel, aged 80, he had been a favourite for the prize for so many years that even his countrymen had started to doubt whether he would ever win.

His most famous works include the 1966 "Windows and Stones," in which he depicts themes from his many travels, and "Baltics" from 1974 about the democracies and dictatorships surrounding the Baltic Sea during the Cold War.

He published "The Sorrow Gondola" in 1996 with work that had been written before the stroke and the "The Great Enigma."

Born April 15, 1931, Transtromer grew up alone with his teacher mother in Stockholm's working-class district after she divorced his father, a journalist. He started writing poetry while studying at the Sodra Latin school in Stockholm and his work appeared in several journals before he published his first book of poetry, "17 poems," in 1954 to much acclaim in Sweden.

He studied literature, history, poetics, the history of religion and psychology at Stockholm University and worked briefly as an assistant at the university's psychometric institution.

But he would spend the majority of his professional life in the much less glamorous settings of state institutions in the small Swedish towns of Linkoping and Vasteras, where he lived in a terraced house with his wife Monika, a nurse, and their two daughters. He first worked at an institution for juvenile offenders and later at a state-funded labour organization, where he helped disabled people choose careers and counselled parole offenders and those in drug rehabilitation.

Meanwhile, he developed his succinct writing style together with his longtime friend, author Lars Gustafsson, as a response to the intense language of Swedish modernist poets.

"We compared our manuscripts and warned each other not to become too like the big names, (Gunnar) Ekelof and (Erik) Lindgren," Gustafsson recalled in a 2011 interview with the AP.

"We were striving, nearly instinctively you could say, in another direction. Not quite toward more simplicity, but maybe toward simpler diction."

For decades, Transtromer also had a close friendship with American poet Robert Bly, who translated many of his works into English. In 2001, Bonniers published the correspondence between the two writers in the book "Air Mail."

Transtromer's poems became infused with his love of nature and were often built around his own experiences: commuting to work, watching the sun rise or waiting for nightfall. But underneath the ordinary there was also something secretive, where he explored existential questions, death and disease.

He wove in imagery of Sweden's barren landscape, or returned to a childhood home on an island in the archipelago off the east coast where his grandfather worked as a ship pilot.

Transtromer travelled to faraway places such as Sierra Leone and the Central African Republic, and his interest in classical music to shone through in his poetry through references to composers and the use of musical rhythms. He was an avid amateur pianist and continued to play with his left hand after the stroke.

In the 1960s and 70s he was often criticized for the religious dimensions of his work and the lack of social commentary that were favoured among the leftist Swedish intellectuals dominating the public debate at the time. But he didn't waver.

"So much has happened. Reality has eaten away so much of us. But summer, at last," Transtromer wrote in the poem "Summer Grass."

"A great airport -- the control tower leads down load after load with chilled people from space. Grass and flowers -- we are landing. The grass has a green foreman. I go and check in."

Transtromer is survived by his wife Monika and their daughters, Emma and Paula. Funeral arrangements weren't immediately announced.