Frederik Prausnitz, 84, who died Nov. 12 at his home in Lewes, Del., was an author, teacher and internationally active conductor who provoked controversy in his quest to promote contemporary classical music.

The German-born Mr. Prausnitz guest-conducted orchestras in the United States and Europe while serving on the faculties of the Juilliard School in New York, the New England Conservatory in Boston and the Peabody Institute's conservatory in Baltimore.

He also worked in London with the BBC and New Philharmonia orchestras. "The BBC paid the worst," he said, "because it was so prestigious."

Despite a keen reputation as a conductor, he did not seek a commercial career. His recordings were infrequent but notable, including works by Carl Ruggles ("Lilacs" and "Portals"); William Walton ("Facade," with Dame Edith Sitwell reading her poetry); Elliott Carter (Double Concerto and Variations for Orchestra); and Roger Sessions (Rhapsody for Orchestra, Eighth Symphony and "Montezuma").

Sessions dedicated his Ninth Symphony to Mr. Prausnitz, who conducted the piece with the Syracuse Symphony Orchestra of New York.

His term in Syracuse, in the early 1970s, was contentious. Although his programming decisions were described as bold, they did not receive unanimous admiration by the orchestra's board and financial backers. However, in 1974, he received the Gustav Mahler Medal of Honor from the Bruckner Society of America for his consistent championing of the composer's work.

Stern-looking, with formally aristocratic features, Mr. Prausnitz could be witty and resourceful, especially to meet a musical goal.

While at Juilliard in the 1950s, he was forbidden by the school's president, William Schuman, to include Mahler on the program during a tour of Europe. "I had to sneak the adagietto from Mahler's Fifth Symphony in as an encore," he said.

Frederik William Prausnitz was born in Cologne, Germany, on Aug. 26, 1920. His father, a physician, disapproved of his son's interest in music, which he viewed as frivolous. His mother, a pianist, was far more accepting.

In the late 1930s, during the Nazi rise, his parents sent him to live with a family in Philadelphia to avoid compulsory service in the German army. The rest of the family arrived in short time.

He attended Juilliard from 1941 to 1945 and worked at the school through 1961. He served as assistant dean of the school; taught conducting and chamber music; and conducted the student orchestra.

After conducting the New England Conservatory's symphony orchestra to critical hosannas in the 1960s, he was invited to become music director of the Syracuse orchestra in 1971. The group, only a decade old, had a burgeoning reputation.

Reviewers admired his contemporary programming and, by his own account, he tended to ignore the grumbles from board members. As tensions peaked, Mr. Prausnitz went to the podium one night during intermission and asked for public backing.

A committee formed to help him, but it had little effect on the board, which seemed intent on buying out his contract in 1974 with a terse statement: "A great basketball coach can make the players better than they can play . . . and you have just not done that for us."

His longest affiliation was with the Peabody Conservatory, which he joined as conductor of its symphony orchestra and opera in 1976. When he retired 21 years later, he had been director of its conducting program and conductor of its Contemporary Music Ensemble.

His books included "Roger Sessions: How a 'Difficult' Composer Got That Way" (2002) and "Score and Podium: A Complete Guide to Conducting" (1983).

The second, filled with his own pen-and-ink caricatures, included an aphorism: "Keep in mind from the start that the podium is a place on which to stand, not to walk or dance. Fancy footwork belongs in the boxing ring."

His marriages to Evelyn Prausnitz and Marion Prausnitz ended in divorce. His third wife, Margaret Britten Prausnitz, whom he married in 1961, died in 1999.

Survivors include two children from the third marriage, Sebastian Prausnitz of Baltimore and Maja Prausnitz of London; a brother; and three grandchildren.

Frederik Prausnitz spent 21 years of his controversial career at Baltimore's Peabody Institute.