It seems that lightning does strike twice: This May 14, when Pierre Boulez conducts the Chicago Symphony Orchestra in an all-Bartók concert at Carnegie Hall, he will be continuing two long-standing relationships‹with this orchestra and with this composer. Boulez first conducted the Chicago Symphony in 1969, when the program included, exactly as it will in Stern Auditorium this month, Bartók's First Piano Concerto‹with, indeed, the same soloist: Daniel Barenboim. The Boulez-Bartók connection goes back even further‹to the time when Boulez gained his most important break as a conductor, substituting for Hans Rosbaud at the 1959 contemporary music festival in Donaueschingen, in southwest Germany.

"Rosbaud was ill," recalls Maestro Boulez, "and they asked me to take over the same program, which consisted of new pieces except for Bartók's Miraculous Mandarin Suite at the end. On short notice, I undertook the task with what we call 'the energy of despair.' Anyway, people seemed to like how it went, and that was responsible for a lot of opportunities for me."

Among those opportunities were invitations to conduct two of the great orchestras of Europe, the Concertgebouw of Amsterdam and the Berlin Philharmonic, initiating an international career that Boulez is still pursuing at the age of 80.

Recently the conductor was in Berlin, where he celebrated his birthday (March 26, the day after Bartók's) by leading the Chicago Symphony in the all-Bartók program he brings to Carnegie Hall: Bartók's First Piano Concerto preceded by the composer's Four Pieces, Op.12, a score favored by few other conductors, but for which Boulez has a special affection.

"It defines the beginning of Bartók's style very precisely," he says about Four Pieces, "especially the scherzo, which is so close to The Miraculous Mandarin." (Indeed, there is a hectic, almost savage momentum here, close to the pounding of city streets and sexuality in the ballet that was to follow.) "There is a hesitation between what will become the real Bartók and other influences, which I find very touching."

Then, at the other extreme, Boulez's Carnegie Hall program ends with the Concerto for Orchestra, Bartók's last and most popular work. Sixty years after its first performance, this remains one of the few 20th-century pieces in the standard orchestral repertory, a fact that Boulez regards with some dismay.

"I find it disheartening sometimes that the same pieces are always performed. For example, I wish Schoenberg's Five Pieces, Op. 16, and his Variations were played more often. As for Berg's Three Pieces, Op. 6, if you put Mahler's name on the score, it would be done all the time."

Asked about works later than Bartók's Concerto for Orchestra, Boulez immediately mentions Luciano Berio's Sinfonia. "I understand the economic concerns that affect orchestras' programming, but there are also artistic concerns that ought not to be there."

Among his own orchestral scores, the one enjoying most success at the moment is his set of Notations, which Barenboim will perform at Carnegie Hall with the Chicago Symphony the night after Boulez's Bartók concert, programming it between Wagner's Prelude to Act I of Parsifal and Beethoven's Seventh Symphony. Boulez sees this program as a demonstration of the development of the orchestra, from a string-dominated ensemble in the Beethoven through the wind-string equality of the Wagner to the parity accorded the percussion in his Notations.

Notations spans Boulez's musical life, beginning in 1945, when he composed 12 piano miniatures and called them Douze Notations. He believed them lost, but those very early compositions resurfaced in the mid-1970s and Boulez decided their ideas had a potential he had been unable to exploit as a 20-year-old. He therefore began recomposing the pieces for a large orchestra of 115 players, so that these bursts of youthful imagination could be developed, amplified, and dazzlingly colored.

The Chicago Symphony's concert on May 15 will include the five orchestral Notations that have so far appeared, all of which were first performed by Barenboim, though Boulez has also conducted them often.

"There is not that much freedom for the conductor, but even so, when other people conduct this music, the musical gestures become slightly different," he notes. "I am myself on the nervous side, and I appreciate it when other people are calmer, as Daniel is. He makes the sonority weightier, whereas with me it would be more transparent."

Paul Griffiths writes frequently about the arts.