Harper Lee, author of the beloved novel "To Kill a Mockingbird," is one of the most reclusive figures in American letters.

		"MOCKINGBIRD: A PORTRAIT OF HARPER LEE" By Charles J. Shields Holt ($25)

Now 80, the Pulitzer Prize-winning author has refused to talk to reporters for years about anything, including her popular novel -- which still sells nearly a million copies a year -- and why she never published another book.

She also refused to talk to biographer Charles J. Shields, but he was not deterred, interviewing about 600 people who have known her over the years and spending four years researching everything he could find about her life.

The result is a fascinating look at both Lee and her book, a classic coming-of-age tale set in a small Alabama town and featuring such memorable characters as Scout, Boo Radley and Atticus Finch.

Why does Lee, whose family and friends call her by her first name, "Nelle," so rigorously protect her privacy?

Shields explores the question in great detail. He also includes amusing anecdotes about Lee's childhood in Monroeville, Ala., where she was a tomboy and began to write stories on an old Underwood typewriter with her next-door neighbor, Truman Capote.

She attended Huntington College and the University of Alabama, where she ignored makeup, preferred jeans to dresses and solitude over parties and was known for her sense of humor and salty language.

Shields also examines her move to New York and agonizing attempts to write "To Kill a Mockingbird," struggling with the novel's point of view and rewriting it three times over several years.

The book's spectacular reception shocked and surprised Lee, Shields writes. She was delighted with the mostly glowing reviews and fan mail, and submitted happily to interview requests.

But that was before she settled down to try to write the dreaded second novel, partly in her Manhattan apartment and partly in Monroeville, Ala., where so many neighbors popped in that she hid at the country club.

There were other disruptions, including working with her agent on film negotiations (Lee wanted Spencer Tracy to play the lead in the movie version, but he was unavailable; she would later become good friends with Gregory Peck, who got the part -- and an Academy Award.)

Yet, reporters kept asking Lee about her second novel, and the questions would continue for years, contributing to her decision to stop doing interviews.

Lee's older sister, Alice Lee, became her spokeswoman, and told a reporter at some point that a burglar had broken into her sister's apartment and stolen her manuscript.

Another reason Lee may avoid the press is the persistent rumor that Capote actually wrote "To Kill a Mockingbird." Shields makes it clear that Lee was in fact the author, but Capote "never went to any strenuous lengths to deny" the story.

Even so, Lee and Capote were lifelong friends, and he recruited her to help him research his most successful book, "In Cold Blood."

Some of the most interesting material in this biography is about their time together in Kansas working on Capote's book.

Today Lee lives a quiet life in Monroeville, sharing a house with Alice, 95, who still practices law, and she also keeps an apartment in New York. Neither woman married. They are often seen around town going to the post office, where Lee "gets hundreds of letters," or eating at the local diner and debating later about who pays the check.

Although his subject never cooperated with Shields, a former teacher, reporter and author of several nonfiction books for young people, he manages to bring her vividly to life in this impressive biography.