Reserved Harper Lee co-operates on biography

A forthcoming biography of To Kill a Mockingbird author Harper Lee will offer a rarely heard perspective: that of Lee herself.

The Mockingbird Next Door by Marja Mills will cover topics ranging from Lee's childhood in Alabama to why she never wrote a follow-up to her acclaimed, Pulitzer Prize-winning novel, Penguin Press announced Tuesday.

Mills, a former reporter for the Chicago Tribune, garnered the co-operation of Lee as well as her friends and family members.

Penguin has not yet announced a date of release for the book.

Lee, who celebrates her 85th birthday on Thursday, published To Kill a Mockingbird in 1960.

Inspired by events and peoplefrom Lee's childhood in Monroeville, Ala. (where she was best friends with fellow author Truman Capote), the legal tale about racial inequality and loss of innocence was an instant bestseller and won the Pulitzer Prize in 1961.

Over the years, however, Lee withdrew from public appearances and rarely talked to the media about herself or her novel, whichis considered an American literary classic.It inspired a beloved 1962 film adaptation starring Gregory Peck.

Though she never published another novel after Mockingbird, she has published essays or letters on rare occasions. Most recently, she penned a 2006 missive for Oprah Winfrey's O, The Oprah Magazine sharing details of her lifelong love of books.