John F. Kennedy preferred the Rat Pack to Rachmaninov, but classical music still held enough cultural sway that he (at the urging of the Mrs.) endured evenings at the White House with the day’s cutting-edge composers. It’s hard to picture President Bush making time for photo ops with Arvo Part or Philip Glass; even sax-player Bill Clinton made no apologies for naming Kenny G as his favorite musician.

In his book, “The Rest Is Noise: Listening to the 20th Century,” New Yorker music critic Alex Ross explores classical music’s plummet from cultural eminence to a time when few can name more than a handful of living composers. He tells it matter-of-factly, refreshingly free of those-were-the-days wistfulness.

To non classical fans, the tale of a century-long battle for the heart of classical music may not sound like a page-turner, but Ross’ portrayal of power plays and bitter battles should appeal even to those who haven’t seen an orchestra pit in years. There were hints that music’s old guard held a precarious place at the century’s beginning, but the chaos didn’t really start until late in the first decade.

That’s when German composer Arnold Schoenberg developed his 12-tone technique, making atonal music that replaced traditional harmonies. From there, the classical world splintered off into “us or them.” Composers who stuck with the tonal system worried for their relevance — especially after World War II, when traditional classical music suffered from an association with the Nazis and fascism.