Susan J. "Sue" Boulden, who gained notoriety throughout the Episcopal Church and parts of the Anglican Communion for her outspokenness on human rights and religious issues, died Tuesday following open heart surgery at West Penn Hospital. She would have been 64 yesterday.

Ms. Boulden, of Oakmont, was a familiar figure at Episcopal gatherings, both in the Pittsburgh diocese and on the national scene. Wearing buttons boosting her favorite causes, she would corner clergy, laity and news media to ensure all were aware of not only what she believed, but why.

"She was, No. 1, outspoken," said the Rev. Harold T. Lewis, rector of Calvary Episcopal Church in Shadyside, where Ms. Boulden was a member. "But No. 2, she was indefatigable. She never seemed to run out of steam and always would take anybody on."

Ms. Boulden was fervent and sincere about her causes, and moved fluidly among them. Racial equality and the rights of gays and lesbians within the church were just as important to her as her anti-abortion stance. For her, life was seamless; her love of people was surpassed only by her belief in justice.

She was active in Progressive Episcopalians of Pittsburgh, or PEP, a group she helped form in the wake of the 2002 diocesan convention after a resolution was passed that declared the diocese would no longer accede to national church canon it felt contravened "the historic catholic faith."

She also was a key supporter of the national group Via Media USA that PEP was instrumental in forming.

In addition, Ms. Boulden was diocesan coordinator for Integrity/Pittsburgh, an advocacy group of gay and lesbian Episcopalians, and a contributing writer to Voice of Integrity, the group's national publication.

While she was a former member of the diocesan council and a member of the Episcopal Women's Caucus, she may have been best known for her opposition to Bishop Robert W. Duncan Jr.

Although an early supporter of the bishop, she later became one of his staunchest opponents because she believed his orthodox views disenfranchised gay and lesbian members of the church. Nevertheless, she held a deep affection for the bishop; her term of endearment for him was "Bishop Doughnuts," a play on his last name and the doughnut franchise.

In her curious accent -- a melding of her native British brogue, an adolescence spent in West Virginia and an adult life in Pittsburgh -- she would frequently tell people: "He is driving me right around the bend."

Her sense of humor was often directed at herself. Her e-mail address was "bovinesue," a reference to the two cow heart valves that she'd been living with for the past five years. She was an inveterate e-mailer, sending out scores each day on topics ranging from the Anglican Communion to animal shelters.

Other faiths also held great interest. Her stepdaughter's family is Jewish, and Ms. Boulden took great delight in attending her grandchildren's bar and bat mitzvahs.

"She wasn't just Episcopalian," said her stepdaughter, Mimi Dollinger, of Bloomington, Ind. "She was ecumenical.

"What interested her was how people do things differently, but how much we have in common. It gave her a new way of looking at things in her church."

Born in Nottingham, England, during World War II, she moved with her family to Chester, W.Va., in 1956. She graduated from Hamilton College in Clinton, N.Y., and also earned a master's degree from Pittsburgh Theological Seminary.

She entered the hospital several days ago for surgery to replace her heart valves.

In addition to her stepdaughter, she is survived by her husband, Richard, of Oakmont; a brother, Jonathan Alder, of the Strip District; and three grandchildren.

Visitation will be from 2 to 4 and 7 to 9 p.m. tomorrow at English-Bertucci Funeral Home, 378 Maryland Ave., Oakmont. A memorial service will be held at 11 a.m. Saturday at Calvary Episcopal Church, 315 Shady Ave., Shadyside.