Joseph Küffner's Leçon No. 9, Op. 168 is part of his collection "60 Lessons for 2 Guitars," which represents significant pedagogical material for guitar students. Küffner was a prolific German composer who wrote extensively for guitar during the early Romantic period. His duets are known for their melodic charm and technical accessibility, making them popular teaching pieces that develop coordination between two players while maintaining musical interest.