Filed at 11:04 a.m. ET

WASHINGTON (AP) -- The public gets a behind-the-scenes view into the private Supreme Court this week with release of the personal files of the late Harry A. Blackmun, the justice who authored the 1973 decision that legalized abortion.

Blackmun's paper legacy, filling more than 1,500 boxes, will be unsealed Thursday on the fifth anniversary of his death.

It's been more than a decade since intimate details of the court's inner workings were revealed in Justice Thurgood Marshall's papers, which elicited bitter criticism within the court because the papers include secret memos and unpublished draft opinions in controversial cases.

Most current justices are expected to ensure their files and any embarrassing secrets they might hold will be protected long after their deaths.

Blackmun, like Marshall, served 24 years on the court and into his 80s. He accumulated far more correspondence than Marshall.

The appointee of President Nixon ``took copious notes and never threw away any of his papers,'' Washington lawyer David Frederick said.

Because Blackmun retired in 1994, however, information in his papers will tend to be dated.

``My expectation is the steak may not live up to the sizzle,'' Supreme Court historian David Garrow said. ``There will be some human interest morsels, but those are few and far between relative to the huge amounts of correspondence that is about how to word opinions in cases that most people forgot the week after they were announced.''

Of the most interest will be letters and notes about his handling of abortion cases, as well as any insight into Blackmun's conversion from a conservative capital punishment supporter to one of the court's most liberal members who wrote before his retirement: ``I no longer shall tinker with the machinery of death.''

His authorship of Roe v. Wade brought him more than 60,000 angry letters and repeated threats on his life.

Blackmun, who died at age 90, served with eight of the current nine justices. Stephen Breyer was chosen as his successor in 1994.

Marshall had a prearranged agreement for the Library of Congress to open his files immediately after his death, in 1993. The 173,700 documents revealed details of the court's back-and-forth deliberation in cases involving issues like abortion. Chief Justice William H. Rehnquist sharply criticized the decision to release the papers.

Blackmun also donated his papers to the Library of Congress, more than 530,000 items, with a release date five years after his death.