Mark Kozelek is an American singer-songwriter and guitarist known for his work in the bands Red House Painters and Sun Kil Moon. He is known for his introspective and poetic lyrics, which often deal with themes of love, loss, and mortality. Kozelek's music has been described as "slowcore" or "sadcore," characterized by its slow, melancholic melodies and sparse instrumentation. He has released numerous albums over the course of his career, both as a solo artist and with his bands, and is highly regarded by many critics and fans.