Daniel C. Dennett, one of the most widely read and debated American philosophers, whose prolific works explored consciousness, free will, religion and evolutionary biology, died on Friday in Portland, Maine. He was 82.

His death, at Maine Medical Center, was caused by complications of interstitial lung disease, his wife, Susan Bell Dennett, said. He lived in Cape Elizabeth, Maine.

Mr. Dennett combined a wide range of knowledge with an easy, often playful writing style to reach a lay public, avoiding the impenetrable concepts and turgid prose of many other contemporary philosophers. Beyond his more than 20 books and scores of essays, his writings even made their way into the theater and onto the concert stage.

But Mr. Dennett, who never shirked controversy, often crossed swords with other famed scholars and thinkers.