Although Martinů’s music is lavishly documented on recordings, it is not so often heard live. One problem is that there is too much of it. His catalogue runs to about four hundred scores, including sixteen operas, fifteen ballets, thirty or so concertante pieces, and chamber works for every conceivable instrumental combination. (If you have a group consisting of a clarinet, a horn, a cello, and a snare drum, you’re in luck.) History tends not to favor hyper-prolific composers, who are suspected of producing music by the yard. Yet, even when Martinů seems to go on autopilot, the journey remains idiosyncratic and unpredictable. There’s an inherent tension in his mixture of materials. He is the kind of figure who profits from Botstein’s summertime festivals, which, for thirty-five years, have demonstrated how much great music exists outside the standard repertory. After days of immersion, I wanted to hear still more.