Leonard Burkat, 73, whose program notes are used by orchestras and ensembles around the world. Burkat joined the Boston Symphony Orchestra in 1946 and served as administrative director of its Tanglewood Music Center in western Massachusetts. He was responsible for program planning and selection of soloists and guest conductors for the symphony and the Boston Pops. In 1963, he joined Columbia Records and managed its Masterworks and Epic Classics labels. In 1973, he founded the Leonard Burkat Program Note Service, which supplied notes on musical performances for such orchestras and music groups as the Academy of St. Martin-in-the-Fields, Lincoln Center, the Mostly Mozart and Berkshire Choral festivals. He was also a music critic for the old Boston Evening Transcript and former deputy chief of the Boston Public Library's music department. In 1987, France honored him with a Chevalier of the Order of Arts and Letters for his study of Olivier Messiaen and other French artists. In Danbury, Conn., on Sunday of Paget's disease, a degenerative bone disorder.