JAKARTA, Indonesia (AP) — Benedict Anderson, a Cornell University scholar who became one of the most influential voices in the fields of nationalism and Southeast Asian studies, died Sunday in Indonesia. He was 79.

Anderson died in his sleep during a visit to the city of Malang, Indonesian media reported. The cause of death was not immediately known.

"This is to inform you that Ben Anderson has passed away in Java: the land and its people he loves most," Thai historian Charnvit Kasetsiri, Anderson's close friend and colleague, said in an email to fellow scholars. Indonesians reacted with an outpouring of tributes on Twitter and Facebook.

Anderson is best known for his 1983 book "Imagined Communities: Reflections on the Origin and Spread of Nationalism," whose admired but debated thesis is that nationalism is largely a modern concept rooted in language and literacy. Its publisher, Verso Books, said it had been translated into more than two dozen languages.

"Many readers of 'Imagined Communities' did not know that his knowledge of Southeast Asian languages gave him insights into Indonesian, Thai, and Philippine political culture and history," said Prof. Craig J. Reynolds of Australian National University.

Anderson's influence was not limited to the sphere of theory, as he engaged with the contentious issues of the day with a rigorous analysis and dry wit that inspired his students.

"Throughout his life, he inspired successive generations of students to brush history against the grain by similarly marshaling every ounce of their intellectual creativity and courage to look at history and politics in totally new and greatly more profound ways," said Steve Heder, a research associate at London's School of Oriental and African Studies who studied under Anderson at Cornell.

Born to Anglo-Irish parents in 1936 in Kunming, China, Benedict Richard O'Gorman Anderson grew up in California and was educated at Cambridge and Cornell, where he studied Southeast Asian politics.

His early specialization in Indonesia turned out to be both a curse and a blessing. On one hand, a near-forensic analysis of Indonesia's bloody 1965 coup that he wrote with fellow scholar Ruth McVey led to him being banned from the country until 1999. The "Cornell Paper," as it came to be known, questioned the conventional wisdom that the coup was the consequence of an abortive communist uprising, suggesting instead premeditation on the part of the army.

But while retaining an active interest in Indonesia, Anderson's enforced absence from the country encouraged him to turn his energies elsewhere, with Thailand becoming another specialization by the mid-1970s. He learned enough Thai to co-author a 1985 collection and study of translated modern Thai short stories.

Anderson's most influential work on Thailand was his 1977 essay "Withdrawal Symptoms," which analyzed the social forces behind a 1976 counterrevolution in Thailand just three years after a student-led revolt toppled a military dictatorship.

"His scholarship and commitment to progressive political change meant that he was an icon for scholars in the region and for all those who have studied the region," said Kevin Hewison, a professor of politics and international studies at Australia's Murdoch University. "His analysis of Thailand's 1970s political turmoil remains unsurpassed and is as important today as it was when published."

Thailand is currently under military rule after another coup last year.

Anderson later turned his attention to the Philippines — learning Spanish so he could study colonial-era documents — which led to his last major book, 2005's "Under Three Flags: Anarchism and the Anti-Colonial Imagination."

In a blog posting, Verso Books said Anderson had been working recently on finalizing his memoir, "A Life Beyond Boundaries," which is scheduled for publication next year.