Librarian of Congress Daniel J. Boorstin presented Congress yesterday with a report on books and literacy that paints the nation's decreasing involvement with its literary heritage sunny side up.

The report, a 50-page meditation on "Books in Our Future," notes that one American adult in eight can't read books and one in two doesn't.

But it says the electronic onslaught of television and computers offers more opportunities to expand the nation's pool of readers than it offers competition for their time.

Computers have made publishing easier and more profitable, the report says, and television has brought vast new audiences of readers to works like "Roots" and "Brideshead Revisited."

"Each new technology changes the environment for the Culture of the Book . . . ," the report says. "The telephone, phonograph, radio and television . . . have made the silence that facilitates reading harder than ever to find. But they have also made the boundless choices and personalized experience of the book more welcome and more necessary.

"The enemy of the book is not technology, but the illusion that we could or would abolish the Culture of the Book," the report says. Technology should and can be the ally in abolishing both the inability to read books and the unwillingness to do so, it says.

The report calls for the abolishment of illiteracy in the United States by 1989, but offers no specific new program for accomplishing such a major national goal. Instead, it provides a curious laundry list of "encouraging examples of what we all can do." They range from installing a "family library" in the White House to printing cereal boxes that plug bookish television programs.

"The Oh Boy Corp. of San Fernando, Calif., carries a library promotion message on many of its frozen food packages . . . ," the report says. "Hilton Hotels often furnish bookmarks for guests in their rooms."

Sen. Charles McC. Mathias (R-Md.) in accepting the report for the Joint Committee on the Library that he chairs, told a news conference that in requesting the report Congress was seeking to find out "Is the computer driving the book out of the business?"

"The answer here is that it's not," he said. He praised the report as "interesting, enlightening and instructive," and said the information it contains is vital to Congress as it seeks to budget its information-gathering resources.

Boorstin, questioned by reporters who appeared uniformly confused by the report, acknowledged that the world of book readers is hard to quantify.

While statistics exist on the buying and selling of books, he said, those on the actual reading are extremely elusive.

"Reading has often been compared to sexual activity," he explained. "Much of it takes place in bed and few are prone to underrate the prowess they bring to the task."

In the last analysis, he said, no one knows whether you've really read a book, how you've read it or what you've gotten out of it but you.

While illiteracy and aliteracy, described as the unwillingness to read, are the major threat to the culture of the book, the report says, there is also "a threat from our hasty readiness to exaggerate or misconceive the promise of new technologies," and assume "that the Culture of the Book is a thing of the past."

"Most disturbing is the widely noted decline in emphasis on reading and writing in our elementary and secondary schools . . . Instead of more 'difficult' works that extend the vocabulary and increase the reader's confidence, pupils read current and 'newsworthy' items that often prove of only transient interest."

It is a "mirage," the report says, to think "computer literacy" can replace "book literacy."

The $65,390 privately funded report, product of a 25-member committee of scientists, educators and scholars, says computers and books will continue to coexist and enrich each other.

But it says books will always have unique advantages.

"The book is independent of outside power sources," the report says, it "can be hidden under a mattress or smuggled into slave nations." Best of all, it is "always 'user friendly.' "