Acquired Immune Deficiency Syndrome--they don't know what causes it or how to treat it.

But scientists and doctors are working on it, and the results from an April symposium involving 13 medical experts have been written up in a new book, "The AIDS Epidemic," which was praised last evening at a reception sponsored by Sen. Edward M. Kennedy (D-Mass.) and the book's publisher, St. Martin's Press.

Kennedy, who left the Senate floor briefly and was joined by fellow Sens. Howard Metzenbaum (D-Ohio) and Spark Matsunaga (D-Hawaii), called the book the "greatest compilation of material on AIDS." Kennedy predicted it would make "a major contribution in the understanding and awareness of the issue."

About 50 guests, including the Rev. William J. Byron, Catholic University's president, gathered in the Hart Senate Office Building to honor Dr. Kevin M. Cahill, who edited the book. Rep. Ted Weiss (D-N.Y.), who wrote a segment for the book titled "The Public's Response," also attended.

Kennedy, when asked whether public action over the issue has been lagging because AIDS is perceived as a "gay disease," replied, "I would like to believe not. There's a movement now to find a cure for AIDS and that's what's important."

AIDS is a disease that attacks the body's immune system. Victims are left vulnerable to forms of cancer, pneumonia, and other diseases. Since AIDS first reached public notice in 1981, male homosexuals, Haitian immigrants and intravenous drug users have been the groups most affected by the disease.

"Seventy percent of AIDS patients die of parasitic and other infectious diseases. As more and more were referred to me," Cahill said, "I realized I was in the midst of something truly unique."

The book, he noted, has been "written in a style that will be understandable for the lay public."

The head of the Centers for Disease Control and the former director of the National Institutes of Health were among the experts at the April symposium at Lenox Hill Hospital in New York. "Eight months ago we got no attention when we planned the symposium," said Cahill. "The book gives it AIDS attention."

"Interest is translated into congressional attention, which is translated into funds for the people who do research," said Cahill. The AIDS epidemic has been ignored for too long, causing many victims to "die in neglect and isolation," he said.

Is Cahill optimistic about finding a cure for AIDS?

" 'Optimism' is a funny word. But am I pessimistic? No."