The veteran pianist Paul Bley has collaborated with many of the greats, including Charlie Mingus, Ornette Coleman, and Jimmy Giuffre, over the course of his long career, so he’s soaked up and shared a lot of great sounds. On Solo in Mondsee, he masterfully balances structure and exploration; the disc’s ten tracks, simply titled “Mondsee Variations I – X,” vary in tone yet flow seamlessly, creating an album that feels like one long crafted meditation. These instant-compositions sometimes feel like songs or hint at standards but delightful detours abound. Bley is like a sly storyteller who skillfully slips in compelling digressions but always manages to gracefully return to the main plot. He keeps you on your toes throughout: a sweet line will suddenly turn dissonant or abstraction will be punctuated by splashes of the blues. (One of the thrills of listening to Bley is hearing the way he shades tonality with atonality.) Even the endings are striking; they both surprise and satisfy. Listening to Solo in Mondsee is a chance to listen in as a pianist’s rich musical thoughts unfold in real time.