On Oct. 17, 1994, Dave Grohl stepped into Robert Lang Studios in Seattle with a collection of songs to record. He played every instrument himself and, with the help of producer Barrett Jones, completed what would become the Foo Fighters’ self-titled debut album in just a week. At the time, he was known to the world as a surviving member and drummer of Nirvana. No one, including Grohl himself, could have anticipated what would happen next and, 20 years later, he seems to still question why it did at all. Foo Fighters’ eighth studio album, Sonic Highways, coincides with a documentary series of the same name that aired on HBO this fall. Each episode took the band to a different city across the country that has developed a seminal music scene over time. In a week’s time, Grohl, who also served as director, conducted interviews with native musicians to get a feel for how the city’s history impacted the music and vice versa. He then wrote lyrics based on the band’s experiences to lay over sketches of songs that came to fruition with the help of producer Butch Vig, as well as musical guest appearances by Joe Walsh, Ben Gibbard and Rick Nielsen. Lyrically, this is Grohl at his most introspective and, as always, he can rely on his band to help him lay some serious groundwork to carry the weight of his words. “Something From Nothing” and “The Feast and the Famine” are the Foos at their best—in their raucous element—while a track like “I Am a River” showcases a softer side that the band has continued to refine over the years. The project, like its creator, is ambitious and while the songs are great, that’s not what makes Sonic Highways a success. The achievement here is in the rare ability to showcase the importance of process over product, and that comes from Grohl’s genuine curiosity into our collective musical identity as well as his own.