Hey there, I'm Glenn Weldon, and this is NPR's Book of the Day.

Today we're bringing you two recent books about world-changing moments in the history of music.

In a minute, we'll hear from a married couple whose latest kid's picture book tells the fascinating and very twisty story of the creation of the saxophone.

But first up, William Robin and Carrie O'Brien are a pair of

musicologists who've written on minimalism documenting a musical movement. It traces the history

of this mysterious and often misunderstood musical approach, paying particular attention to the

international music that influenced it and to the many figures, besides its most well-known adherents

like Philip Glass, whose vital contributions haven't yet seen their share of the spotlight.

NPR's Noah Caldwell spoke with the authors for all things considered.

In the U.S., national security news can feel far away from daily life.

Distant wars, murky conflicts, diplomacy behind closed doors.

On our new show, Sources and Methods, NPR reporters on the ground bring you stories of real people

helping you understand why distant events matter here at home. Listen to sources and methods on the NPR app or wherever you get your podcasts.

On November 4th, 1964, an ensemble of musicians took the stage at the San Francisco Tape Music Center.

The first thing you hear is this constant reiterating eighth notes played on the piano, sees, this pulse.

William Robin is a musicologist at the University of Maryland.

That night was the debut of an experimental composition.

It was written by a young composer named Terry Riley, but it was the musicians who were

in control of the performance.

They could each choose from 53 musical phrases, all of them revolving around the note C

to play for as long or as short as they wanted, before moving on to the next one.

It was called In C.

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