The rise of the personal computer has spawned a new category of publishing: the compubook.

Books about personal computers are pouring off the presses and disappearing from bookstore shelves at a pace that makes them the hottest items in print.

"Computer books are the liveliest single area in publishing in terms of growth and general bullishness in the bookstores," says John Baker, editor of Publishers' Weekly, the industry's trade journal.

While declining to release specific sales figures, John L. Disem, vice president of McGraw-Hill's book publishing company, reports that sales of books about personal computers "have at least doubled in the last year." John Wiley and Sons, another New York publisher, says it has enjoyed a 250 percent sales growth in the last two years and growth of more than 800 percent since 1979.

"It's comparable with the growth in romance books," said Robert Haft, president of Crown Books, the Washington-based chain with 34 area stores and 125 throughout the country. "It's outselling the entire category of business books--both hardcover and paperback."

Within the last two years, Haft has seen a 400 percent increase in compubook sales, and the stores have quadrupled the amount of floor space allocated to them. Store managers are being sent to computer book seminars, and Crown "is now developing our own computer book best-seller list," Haft said.

"By any parameter you use--sales per square foot, average sales per title, revenue--computer books wipe out anything else we have," said Elwin Lages, computer book service assistant in a McGraw-Hill bookstore in New York.

With over 2,000 compubook titles, the store has one of the largest computer book sections in the country, and "it's the only department in the store with continuingly growing sales," Lages said. In 1981, computer books accounted for 17 percent of the store's sales; by the end of this year, it will account for fully one-fourth, he added.

"The best-selling books are the 'how-to' books that are either machine-specific or about a certain application," said Tom Bennett, the computer book buyer for B. Dalton, the Minneapolis-based bookstore chain that is the largest in the country.

Books on the low-priced machines have done particularly well. Bennett speculated that one reason is that the manuals issued with most machines are difficult for beginners to understand.

"Our growth in 1982 was 150 percent," and it was over 100 percent in 1981," he said. "This year, I'm projecting close to another 150 percent increase--we can't keep this growth up forever, but I can't see when the slowdown will occur."

Peter MacWilliams' "The Personal Computer Book" reportedly is the best seller in the category at B. Dalton, appealing to those who are trying to decide whether to buy a computer.

The logic behind Bennett's optimism is that personal computers still are selling at a rapid clip. Over 3.5 million personal computers are expected to be sold this year, and the publishers figure that every buyer is a potential customer for a personal computer book.

Some publishers now are interested in producing software--the instructions on tape, magnetic disc or cartridge that make computers perform specific tasks or play specific games. Warner Books and Simon & Schuster recently formed computer software divisions. Each of McGraw-Hill's book publishing divisions has a software organization.

Several computer industry analysts believe that the publishing industry could become a powerful force in the rapidly expanding personal computer software market, which some estimate will grow in excess of $5 billion by 1985.