Norwegian pianist Jon Balke’s Book of Velocities is a hard-to-place album. These 19 pieces, which Balke presents as four chapters and an epilogue, might bring to mind specific composers — John Cage, Erik Satie, Morton Feldman, Keith Jarrett — but only in passing. The music sits somewhere in the vicinity of contemporary classical, jazz, and New Age, but it occupies its very own patch of turf. In creating the album Balke didn’t use overdubs or electronics to craft its plethora of intriguing textures. He plays both the keyboard and the inside of the piano — sometimes at the same time — to create tones that investigate the instrument’s timbral range. (His inventive approach reminds the listener that the piano is a percussion instrument as well as a tool to produce harmony and melody.) Despite its low-key nature, this is not an ambient album; the pieces — all under five minutes in length — are packed with gripping details meant for close listening, and silence is as effectively used as any note or chord. Book of Velocities re-imagines what the acoustic keyboard is capable of.