Forensic linguists are able to identify the author of an anonymous piece of writing by tracing it to what the author has been reading, because what we read substantially affects how we write. This suggests, once again, an important lesson for those of us who want to learn how to write well. Inasmuch as what you read determines how you write, you will learn to write well by reading well written material.

The "Prosecutor" magazine, published by the National District Attorneys Association, calls Dr. Donald W. Foster "The Sherlock Holmes of Text Analysis." He earned the praise by repeated success in telling investigators and courts who did or who did not write something under investigation. The FBI used him to determine that Theodore Kaczynski is the Unabomber. So, too, have law enforcement agencies sought his help on the JonBenet Ramsey murder case and the Monica Lewinsky fiasco. He is currently working with investigators on the anthrax problem.

This language expert first came to public attention by revealing that Joe Klein, a former Newsweek political columnist, was the anonymous author of the 1996 best selling novel "Primary Colors." Klein's main character is "a wily politician with an uncanny resemblance to Bill Clinton." Both author and publisher did their best to hide his identity, but Foster found him through analyzing how he writes.

Foster's day job is as an English professor at Vassar College and an expert on Shakespeare. His sideline has become what is called forensic linguistics or stylistic linguistics and attribution. The technique, a sophisticated computer-assisted process that is both art and science, was developed as a means of learning whether a certain literary work was actually written by the person who claimed to have written it or to whom it is attributed.

Even beyond issues of plagiarism, many legal cases hang on the ability to prove who wrote a promise or who did not write a threat. The first step is to examine the questioned text, seeking idiosyncrasies in language and mechanical distinctions. Such factors as whether dashes or parentheses are preferred -- or even how dashes are formed -- are examined. Then the investigator turns to computerized databases and the internet, seeking samples with vocabulary and phrasing that resemble the questioned text.

Foster asserts: "Words are fingerprints, some words and images simply cling like burrs to a reader's brain. You are what you read. When you write, your reading leaves its imprint on the page."

"It can be nearly as important to document a suspect's reading material….No one, not even the most clever offender, can speak or write without borrowing ideas and language from familiar sources."

The cause-effect relation of what a person reads and what this person writes reminds us that the quality of our writing approximates the quality of our reading. If we read junk, we'll write junk; if we read rich literature, we'll write in proportion to it.

When I see the tripe on which many people feed mentally, I understand when they regurgitate tripe. (They don't even need to use a tripewriter.)

One of the most productive things a person can do to write effectively is read effectively written material. We become what we read, and we write as we have read.

Well written texts do not fall into our laps, and we must search for and acquire them. Poorly written material comes to us everyday not only in the popular media but in required academic reading and government publications. Extract the information needed from what you must read, purge your mind of the poison, and then refill it with good reading that nourishes.

If you wish to write well, read what is well written.

-- Dr. Wallace Alcorn appears Mondays in the Austin Daily Herald