Smog is the stage name of the American musician Bill Callahan, known for his distinctive lo-fi sound and introspective lyrics. Active since the early 1990s, he initially released music under the Smog moniker, blending elements of folk, rock, and avant-garde. Callahan's work often features sparse instrumentation and a deep, resonant voice, exploring themes of isolation, love, and existential contemplation. Over the years, he has garnered critical acclaim for albums such as "Knock Knock" and "A River Ain't Too Much to Love," with a style that has influenced a generation of indie artists. In addition to his solo work, Callahan has collaborated with various musicians and continues to be an influential figure in the indie music scene.