June 19. A monolithic innovator of acoustic guitar, Leo Kottke came to his instrument at the age of 11 and discovered the American folk music that became his stylistic canvas via the great Mississippi John Hurt. In 1971 Kottke was singed by fellow guitar giant John Fahey to his Takoma label for the landmark 6 & 12 String Guitar, a top-selling psychedelic synthesis of blues, pop, classical, and folk styles highlighted by the utterly blazing "Vaseline Machine Gun." Kottke, a patron saint of the modern acoustic revival, makes a long-awaited return to the Catskills with this date at Club Helsinki. (Over the Rhine flows June 7; Suzanne Vega visits June 22.) 8pm. $42, $45. Hudson. (518) 828-4800; Helsinkihudson.com.