BEARSVILLE, N.Y. (AP) _ Ian Ballantine, a prolific publisher and one of the first to introduce inexpensive paperbacks to American readers, died of a heart attack at age 79.

He died Thursday on his way to a dental appointment, nephew Tad Wise told the Daily Freeman of Kingston.

Ballantine and his wife, Betty, launched three major paperback companies: Penguin U.S.A., Bantam Books and Ballantine books. He believed that people would read a variety of books if they were affordable and accessible.

Ballantine, who had lived in Bearsville since 1939, had been advised by a doctor to take a break from work, but ``retirement was not in his vocabulary,'' Wise said.

Ballantine still kept an office at Bantam Books in New York City. And he and his wife also worked in Bearsville, about 50 miles southwest of Albany, under the name Rufus Publications. That company, named for Mrs. Ballantine's dog, specialized in illustrated art and fantasy books.

Bantam Books was closed Friday in his honor.

Last month, the Ballantines received the Literary Market Place's Lifetime Achievement award at the New York Public Library.

``He made the product more affordable to the masses,'' said Stanley Walker, the vice president of Reed Reference Publishing and the chairman of the Literary Market Place awards committee.

``The most important thing anyone learned from him is his belief that writing needs to be accessible to the reader,'' Irwyn Applebaum, president of Bantam Books, told the Daily Freeman.

Ballantine and his wife launched Penguin U.S.A. in 1939, reprinting imported classics such as H.G. Wells' ``Invisible Man.''

In 1945, they left Penguin to start Bantam Books. Their first list included ``Life on the Mississippi'' by Mark Twain, ``The Grapes of Wrath'' by John Steinbeck and ``The Great Gatsby'' by F. Scott Fitzgerald.

In 1952, they formed Ballantine books, which concentrated on paperback originals by such authors as Ray Bradbury, Arthur C. Clarke and J.R.R. Tolkien.

Random House bought the company in 1974, and the Ballantines rejoined Bantam, working on books by such authors as Chuck Yeager and Shirley MacLaine.

The New York Times said Ballantine was something of an enigma to his employees, both stern and playful. ``Talking with Ian was a cross between a friendly browbeating and a sprinkling of pixie dust,'' Applebaum said.

Ballantine is survived by his wife; a son, a brother and three grandchildren. Funeral services will be private.