Two of the seven discs are devoted to The Road, a piece only 50 percent completed so far; finished, it will last five hours, in eight parts. Each part is an eight-mile segment of the completed “road”; the nature of the road itself changes, from footpath to railroad track to whatever. Listening for an uninterrupted two-plus hours to the four parts so far available, you get the sense of being in a closed room with the music in the process of being born, the pianist-composer at one end, yourself at the other. There is no sense of reaching beyond that room, of grandly proclaiming great messages in a sold-out concert hall. If ever a piece of music could bring you close to the creative process, this is it.