NO one knows -- not even science -- what causes stuttering. "Our best guess is that it is due to a combination of psychological, neurological and genetic factors," says Dr. Barry Guitar, American professor of communication science and disorders at the University of Vermont in Burlington.

But they do know that it is habit forming and is usually related to stress, according to Dr. Martin F. Schwartz, executive director of the U.S. National Center for Stuttering in New York City.

When a child is learning to speak, or when an adult has to speak in stressful situations (before a large audience, for instance), the stress focuses tension on the vocal cords, closing and locking them. The person struggles to speak but can't do so easily: The struggle becomes a stutter.

"The Book of Lists" enumerated 14 famous stutters. Most of them beat this speech disorder. Let's start with film actor Bruce Willis. He began stuttering at the age of eight. In high school, he joined a drama club and found that his stammer vanished whenever he spoke in front of an audience.

Another film actor, James Earl Jones, discovered the same solution. As a young man, he stammered so badly that at times he was reduced to writing notes. He overcame the affliction with speech therapy and by joining his high school debating team.

Henry Luce, publisher and founder of "Time" magazine and "Sport Illustrated," was born in China to missionary parents. He was sent to boarding school at age fifteen, where he was called Chink. He began to stammer, and became surly and aloof. Eventually, he conquered his stutter by participating in the Yale debating society.

Novelist W. Somerset Maugham's stutter was so severe that it deeply scarred his life. It was much worse when he was nervous, and only in the company of his closed friends did it disappear. His childhood was full of humiliating moments, such as the time he stuttered in school and the whole class screamed with laughter until the teacher pounded the desk and called him a fool. As an adult, he turned down frequent invitations to speak publicly and read on the radio.

Writer Charles Lamb was disqualified from entering university because of his disability. His alcoholism exaggerated his stammer, and he described himself as "a drunken dog, ragged head, seldom shaven, odd-eyed and stuttering."

Plagued by a lifetime of nervous disorders, another Charles - naturalist Charles Darwin, if you will - turned to science because he stuttered too badly to become a minister. His grandfather, Erasmus Darwin, was a good speaker, in spite of his stutter. When asked whether he found his speech impediment inconvenient, he replied, "No, sir, it gives me time for reflection, and saves me from answering impertinent questions."

Like Darwin, Cotton Mather desperately wanted to become a clergyman. He nearly abandoned all hope because he suffered from a bad stammer. He felt sure nobody would understand his sermons. He took heart from the knowledge that Moses stammered and went on to become one of the greatest preachers of his day.

Two athletes were included in the list. Runner Ben Johnson "learned" to stutter by teasing his brother, who stuttered. Unfortunately, the habit stuck and he couldn't get rid of his stammer.

This happened also to former NBA all-star player Bob Love. He believes he started to stammer in imitation of an uncle he loved deeply. His inability to communicate caused him to turn to basketball. After arduous speech therapy, Love has virtually conquered his disorder.

Two European kings were listed to have suffered speech problem. British king Charles I was a lifetime stutter. He ascended the throne in 1623 and addressed his first Parliament by saying, "I am unfit for speaking." Then he sat down.

How can you get rid of stuttering? "The Doctors Book of Home Remedies" offers some timely techniques. For one, it advises that you should not speak faster. "If you're stuttering, maybe it's because you're trying to speak as fast as or faster than others - and you just don't need to."

The book also urges that you record your stuttering (this way, you can catch the speech problem in advance and prevent stuttering before it starts), practice natural breathing (take a relaxed breath through the mouth), and synchronize airflow.

As much as possible, stutters must avoid cola and coffee and sweets. Caffeine and other stimulants reportedly encourage muscle and vocal tensions. Sugar reduction has reportedly eliminated stuttering in some children, the book says.

If you're a parent, don't speak to fast to your children. "When kids try to speak as fast or faster than adults, they often stutter," says Dr. Edward Conture, chairman of the Program of Communication Sciences and Disorders at Syracuse University in New York. "If you speak slowly and evenly to your child, he'll soon get the picture and slow down naturally."

In other words, set the pace.