But right at the beginning of “Country Music” is an acknowledgment that slave songs formed part of early country’s raw material. And then a reminder that the banjo has its roots in West African stringed gourd instruments. The series covers how A.P. Carter, a founder of the Carter Family, traveled with Lesley Riddle, a black man, to find and write down songs throughout Appalachia. And it explores how Hank Williams’s mentor was Rufus Payne, a black blues musician.

It goes on and on, tracing an inconvenient history for a genre that has generally been inhospitable to black performers, regardless of the successes of Charley Pride, Darius Rucker or DeFord Bailey, the first black performer on the Grand Ole Opry. Over and again, “Country Music” lays bare what is too often overlooked: that country music never evolved in isolation.

Each episode of this documentary tackles a different time period, from the first Fiddlin’ John Carson recordings in the 1920s up through the pop ascent of Garth Brooks in the 1990s. Burns has used this multi-episode approach on other American institutions and turning-point historical events: “The Civil War,” “The Vietnam War” and “Jazz.” These are subjects that merit rigor and also patience — hence the films’ length. But country music, especially, demands an approach that blends reverence and skepticism, because so often its story is one in which those in control try to squelch counternarratives while never breaking a warm smile.

“Country Music” rolls its eyes at the tension between the genre imagining itself as an unvarnished platform for America’s rural storytelling and being an extremely marketable racket where people from all parts of the country, from all class levels, do a bit of cosplay.

Minnie Pearl, from “Hee Haw,” came from a wealthy family and lived in a stately home next to the governor’s mansion. Nudie Cohn, the tailor whose vividly embroidered suits became country superstar must-haves in the 1960s and beyond, was born Nuta Kotlyarenko in Kiev, and worked out of a shop in Hollywood. The number of life insurance advertisements sprinkled throughout the photos in the early episodes serve as a reminder of just how contingent the spread of country music was on its sponsors. One salesman recalled determining which homes were tuning in to the Grand Ole Opry on the weekend, and then going to try to sell them insurance on Monday morning.