Call in Atticus Finch.

Only the scrupulously fair lawyer at the center of Harper Lee’s Pulitzer Prize-winning novel, “To Kill a Mockingbird,” could get at the truth in the latest conflict over the reclusive author’s privacy.

The clash erupted again with Tuesday’s release of “The Mockingbird Next Door: Life with Harper Lee,” by former Chicago Tribune reporter Marja Mills. To gather material for her intimate portrait, Mills rented a house in Monroe­ville, Ala., next door to the 88-year-old author and her older sister, Alice, and gradually got to know them. In the book, Mills claims she had “the trust, support, and encouragement” of both sisters.

But in a letter released Monday, Lee insists she never authorized Mills to reveal anything about her private life. “Rest assured, as long as I am alive any book purporting to be with my cooperation is a falsehood,” Lee wrote.

Mills reacted swiftly, issuing a statement of her own in which she asserts that the sisters “gave me their blessing.” She included a 2011 statement by Lee’s good friend, Tom Butts, who said that the Lee sisters “were pleased that Miss Mills was going to preserve . . . stories [of their lives] in a book. . . . All in all the friendship was an open and happy experience for all concerned.”

Author Harper Lee, shown here in 2007, wrote in a letter released July 14 “Rest assured, as long as I am alive any book purporting to be with my cooperation is a falsehood.” (Rob Carr/AP)

Long before its publication, “The Mockingbird Next Door” sparked a similar disagreement. When Penguin Press announced plans for the book in 2011, playing up Mills’s access to the sisters, Lee responded with a statement denying she was willingly participating. Butts released his statement at that time, and today he authorized its release again, according to the publisher.

Lee and her beloved 1960 novel — the only one she has written — are subjects of endless fascination. Her insistence on maintaining her privacy only feeds the public’s appetite for the facts of her life. “The Mockingbird Next Door” was ranked Tuesday at No. 9 on the Amazon bestseller list.

Although Mills finds herself plunged into a controversy over the limits of privacy, she writes in the book that she “didn’t feel . . . entitled to more from [Lee] than she wanted to share.” The book, she writes, is her attempt “to honor all that [the sisters] shared with me.”

Writing in The Washington Post, reviewer Heller McAlpin said, “ ‘The Mockingbird Next Door’ is warm yet wistful, a lament for the books Harper Lee never wrote. It ends on an elegiac note, since by the time Mills was able to complete it, the Lees were fading fast, in separate assisted-living facilities. The world she depicts is sadly gone, but — lucky for us — she caught it just in time.”

Penguin Press stands by the book, saying in a statement: “Mills’ memoir is a labor of love and Marja Mills has done an extraordinary job. We look forward to sharing her story of the wise and wonderful Lee sisters with readers.”

Penguin didn’t respond to a request to clarify why it has persisted in promoting the book as authorized despite Lee’s public opposition.

In her letter Monday, Lee wrote that when Mills showed up in Monroeville, she soon discovered the visitor’s true mission: “Another book about Harper Lee. . . . I immediately cut off all contact with Miss Mills, leaving town whenever she headed this way.”