WASHINGTON (AP) _ As William J. Brennan turns 90, some might say the retired Supreme Court justice fits his own description of the Constitution: ``A tough old soldier that's collected quite a few respectable dents in the line of duty.''

Brennan's birthday is April 25, and friends and admirers have planned a special tribute for the liberal lion they call the 20th century's most influential jurist.

At an April 27 gathering of law clerks, friends and colleagues, Brennan will be presented with a book about his 34-year career on the high court.

Commissioned by the New York-based Brennan Center for Justice, the book is a collaborative effort by lawyers, law professors, journalists and six Supreme Court justices.

``We've attempted to capture the breadth of the Brennan legacy,'' says E. Joshua Rosenkranz, the center's executive director.

Corraling Brennan's contributions is a sizeable task. Before poor health forced him to retire in 1990, Brennan wrote 461 majority opinions and 889 others. Only the late William O. Douglas wrote more opinions at the highest court.

Brennan's rulings led to the ``one-person, one-vote'' principal of political reapportionment and gave news organizations First Amendment protections in libel lawsuits. He also defined obscenity and empowered everyday citizens to use the courts to fight city hall.

The unpublished book, titled ``Reason and Passion,'' also offers new insights into Brennan's style.

Brennan ``never allowed even profound disagreement over important questions of constitutional law to affect the civility and friendship which he extended to every one of his colleagues,'' Chief Justice William H. Rehnquist writes in the forward.

``Each of us was the beneficiary of his legendary warmth and charm, and of his strongly held and incisively presented views ... At times I am sure that Bill Brennan felt I did not benefit enough from the views which he expressed,'' says the conservative Rehnquist.

Retired Justice Harry A. Blackmun, whose chapter focuses on Brennan's influence among his fellow court members, attempts to knock down the notion of Brennan as a behind-the-scenes battler.

``Some commentators have described Justice Brennan primarily as a `consensus builder,' able to pull five justices together to a common ground of his liking. Perhaps so,'' Blackmun writes.

``If that description compels an image of a chambers-visiting, table-pounding advocate _ as in my eyes the description seems to do _ that was not my experience with Justice Brennan.

``He stated his case _ at conference and in any opinion he circulated _ in quiet but firm tones, persuasively to be sure but never in a two-fisted, belligerent or quarrelsome manner. He was a gentleman, first and foremost, and quite content to leave the infighting and elbow-punching to others,'' Blackmun says.

Brennan himself contributed to the book, telling its co-authors he is ``very, very touched'' by their endeavor.

And the lion still has some roar. After noting some court achievements, Brennan writes: ``I do not mean to suggest that we have achieved a comprehensive definition of the constitutional ideal of human dignity.

``We do not yet have justice, equal and practical, for all who do not partake of the abundance of American life. We are still striving toward that goal, and doubtless it will be an eternal quest.''

A frequent visitor to Brennan's office at the Supreme Court building is Justice David H. Souter, who replaced him.

In writing about Brennan's place in legal history, Souter calls his task ``a subject that seems to call for nothing but the obvious.''

``Does anyone seriously wonder,'' Souter asks, ``that the man whose friendship and affection honors us will himself be honored by the consideration of history?''

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EDITOR'S NOTE _ Richard Carelli covers the Supreme Court for The Associated Press.