For a generation after Hiroshima, classical music suffered from a condition that might be diagnosed as a sort of neurosis -- a combination of guilt and fear with symptoms that included sociopathic tendencies and obsessive-compulsive styles. This was not the only thing happening in the field, but it seemed to be the most significant trend.

Classical music, to be sure, does not readily deal in slogans and causes as does pop music or movies, even with a subject as tempting as the atomic bomb. Classics, by definition, are works of art that last; slogans come and go like the ocean's tides.

And in fact the atomic bomb has provided an explicit subject for classical composers only occasionally -- for example, in the "Atomic Bomb" symphonic fantasy (1952) by Japanese composer Masao Oki and "Threnody for the Victims of Hiroshima" (1960), by Krzysztof Penderecki. It has also been used as a motif tacked onto a piece of music in performance -- notably in a modernized production of "Madame Butterfly," two years ago at the Spoleto Festival, which ended with the bomb exploding over Nagasaki.

But what The Bomb did more spectacularly was to change the emotional climate in which composers work, affecting the styles and structures of their music.

Before the atomic bomb, war could still be a subject of celebration in music, as it had been since the beginning of history in works as diverse as "The Agincourt Song," Jannequin's madrigal, "La Guerre" and Handel's "Royal Fireworks" and "Dettingen Te Deum."

Since Hiroshima, the winners have looked upon war in their music as uneasily as the losers. For a long time after the war, even when the music was purely abstract, serious composers tended to be more cautious, formal, oblique and rigidly structured. Emotion was often suppressed within quasi-mathematical structures, and when it came out it tended to be anguished.

In the immediate postwar period, serialism thrived. This is a system, devised by Arnold Schoenberg and elaborated by his disciples, which "organizes" musical structures by ordering their "events" (which can include motifs, pitches, dynamics and rhythms) through imposed, abstract principles of structure. Its practical effect, most of the time, was to put music into a kind of emotional straitjacket -- to eliminate or reduce instinct, intuition and spontaneity. A genius could occasionally use the system to produce a strong emotional impact, but the emotions in those works tended to be anguished.

Some composers who had won international fame in other styles before the war began adopting (or adapting) Schoenberg's system after World War II. The resulting works were often brilliant but seldom appealed to audiences as strongly as their earlier works in other styles. The most notable of these was Igor Stravinsky, who had earlier been seen as the leader of the opposition to serialism. He began to adopt the system in such works as "Agon" (1953), "Threni" (1957) and Movements for Piano and Orchestra (1958). Aaron Copland had been interested in the system even before the war, but he adopted it most fully in such works as the Piano Quartet (1950), the Piano Fantasy (1955), "Connotations" (1961) and "Inscape" (1967) -- music that contrasts sharply with the colorful, popular pieces he had composed before and during the war.

Other composers (such as Milton Babbitt and Charles Wuorinen) were more thorough and systematic in their dedication to serial techniques. They might have been similarly thorough and dedicated without the influence of the war, but it is doubtful that their work would have been as influential. Young composers flocked to the system in the '50s and early '60s. Serialism may have been, in some ways, a musical equivalent of the fallout shelters that were being built during the same period.

With or without serialism, with or without explicit references to the atomic bomb, music in the postwar period was strongly flavored by that traumatic experience. Leonard Bernstein, who was able to be light-hearted during the war with such music as "Fancy Free" and "On the Town," produced "Age of Anxiety" in the immediate postwar years, and lampooned musical optimism in his one-act opera "Trouble in Tahiti" (1951).

Other composers wrote about war without specifically mentioning the bomb: Schoenberg in "A Survivor of Warsaw" (1948); Menotti in "The Consul" (1950); Britten in the "War Requiem" (1961). Although it is not specifically a part of the subject matter in these works, the emotion provoked by the bomb is probably present in the subtext.

A return to more personal, spontaneous and optimistic styles and forms began in the mid-1960s, grew slowly and now seems to be the dominant element in classical music -- analysts have taken to calling it Neo-Romanticism. Like most people of our time, classical composers have confronted the subject of the bomb, recoiled in horror and returned slowly to the practical attitude that life must be continued, as normally as we can manage, even with that shadow looming over us. They may be dancing on a volcano, but at least they are dancing again.