Revisiting some earlier pieces while forging ahead on a high creative level, guitar master Bill Frisell offers a manifesto of sorts with Music IS. The tuneful simplicity of “Thankful,” the wobbly elegance of “Monica Jane,” the slow melodic arc of “Ron Carter,” the angular blues of “Winslow Homer”: Frisell’s broad aesthetic range and sense of invention couldn’t be clearer. His tones on electric and acoustic are endlessly varied, his effects weird yet tasteful, and his harmonic detours always engrossing.