With his umpteenth release in the last few years, pianist Mehldau continues a remarkable evolutionary course, following up the rhapsodic splendor of his recent solo project, Elegiac Cycle, with another fluidly empathetic trio date. It’s a live affair in more ways than one, full of the detours and shameless explorations on-the-fly that Mehldau is wont to make in the course of jazz duty. Mehldau’s debt to the re-inventive impulse, and the classical instincts, in Keith Jarrett’s playing are still identifiable, but his personal voice keeps emerging afresh. The sense of Trio Think is also deepening, as his comrades-drummer Jorge Rossy and bassist Larry Grenadier-get to know each other, as well as what they can get away with, individually. They get away with making piano trio music of a high order, whether rhythmically reshaping “All the Things You Are,” loosening up “Solar,” defining the essence of Mehldau’s lustrous, sad ballad “Sehnsucht,” or waxing shamelessly, artfully romantic on the Radiohead tune “Exit Music (for a Film).” The series title Art of the Trio could be interpreted as presumptuous, but, in this case, art is precisely the right term.