In what marks one of the Library of Congress’ largest releases of judicial documents, the late Supreme Court Justice Harry Blackmun’s personal papers — numbering more than a half-million items — are scheduled to be unveiled to the public Thursday, the fifth anniversary of the controversial justice’s death.

Blackmun, a Nixon appointee who served on the court from 1970 to 1994, participated in the disposition of 3,875 cases — including 800 argued cases — during his tenure. But he was best known for writing the majority opinion in Roe v. Wade, which established the constitutional right to an abortion — a move that netted him “postal bags full of mail,” said University of Iowa law professor Randall Bezanson, a Blackmun clerk during the 1972-1973 term.

Given Blackmun’s propensity to save nearly everything that passed through his chambers, former clerks say, the release should provide one of the most comprehensive looks into the inner workings of the highly secretive institution.

“I would guess that the Blackmun papers will make it a great deal more transparent,” said former Blackmun clerk Benjamin Sharp, a partner in the D.C. office of Perkins Coie.

In 1997, Blackmun donated his papers to the Library — home to the collections of 38 other justices — but stipulated that they not be opened to the general public until five years after his death. Only three news organizations — The New York Times, National Public Radio and PBS’ News Hour with Jim Lehrer — have been allowed a preview prior to the release.

“Our goal was to make sure there was an orderly public release in a manner that enhanced general public understanding of how the court worked,” said former Blackmun clerk and Yale Law School professor Harold Koh, an adviser to the justice’s daughter Sally Blackmun, the estate’s executor.

While much of the material will simply “augment the existing record,” said Edward Lazarus, a former Blackmun clerk and partner at Akin Gump Strauss Hauer & Feld in Los Angeles, the justice’s take on the court’s post-1990 period, not covered in previously released judicial papers, should provide unique insight into the court’s “sharp turn” in favor of states’ rights, as well as into Blackmun’s changing views on the death penalty.

The papers, which fill more than 1,500 boxes and would stretch 630.2 linear feet, are divided into subgroups, such as appointment books, correspondence, case files and briefs. They include everything from Blackmun’s FBI file to some 38 hours of oral history interviews and papers related to his 1997 appearance as Supreme Court Justice Joseph Story in the Steven Spielberg film “Amistad.”

The Library will post a 362-page guide to the collection on its Web site, with plans “down the road” to put some of the offerings online, said LOC spokeswoman Helen Dalrymple.

A decade ago, when the Library opened Justice Thurgood Marshall’s papers to the public — its last major judicial unveiling — after the first black justice’s 1993 death, a minor firestorm erupted when both Marshall relatives and Chief Justice William Rehnquist criticized the release as premature.

Most Blackmun associates — who emphasized his generally collegial relationships with colleagues — don’t anticipate a similar brouhaha.

“Marshall was a fairly ebullient man and might well have been interested in committing his opinions about others to paper,” said Bezanson. “I don’t think you would find much of that in Blackmun’s papers.”

But given Blackmun’s meticulous recording of the justices’ ultra-guarded conferences, it’s not improbable that a few of his notes on the judicial decision-making process could prove uncomfortable for some sitting members of the bench, others say.

“I have little doubt that the justices, at least some of them, were rather this not happening,” said Lazarus. “It hasn’t been that long since Blackmun stepped off” the court.