The Music Man is a musical with book, music, and lyrics by Meredith Willson, based on a story by Willson and Franklin Lacey.

Con man Harold Hill poses as a boys' band organizer and leader, selling band instruments and uniforms to naïve Midwestern townsfolk and promising to train the new band, then skipping town before the instruments arrive.

The musical takes place in 1912, in the fictional town of River City, Iowa. The town is based in large part on Meredith Willson's birthplace, Mason City, Iowa, and the "river" in River City is probably the Mississippi River.

When Harold arrives in River City, he meets his old friend and shill, Marcellus Washburn, who has "gone legit" and is now one of the locals. Marcellus tells Harold that Marian Paroo, the librarian who gives piano lessons, is the only trained musician in town.

"Ya Got Trouble" is his slippery slope argument of what could happen should the citizens of River City fail to recognize the danger the pool hall represents and follow his suggestion for a more wholesome activity. The song contains many types of invalid argumentation ("trouble starts with t, which rhymes with p, which stands for pool").

Winthrop, Marion's 10-year-old brother, has a lisp that makes him shy and self-conscious.

Amaryllis, one of Marion's piano students, secretly likes Winthrop but teases him about his lisp.

Mayor Shinn and his overbearing wife Eulalie MacKecknie Shinn lead the festivities for Independence Day at the high school gym ("Columbia, the Gem of the Ocean") but are interrupted by a firecracker set off by troublemaker Tommy Djilas.

Eulalie MacKecknie Shinn and her less-than-graceful entourage of "Grecian urns" are one of the delights of The Music Man.

Seventy-six trombones caught the morning sun
With a hundred and ten cornets right behind
There were more than a thousand reeds
Springing up like weeds
There were horns of ev'ry shape and kind