Few jazz heavies have engaged with pop music more successfully than Herbie Hancock, but he outdoes himself on The Joni Letters. On this late-career gem he complements classics written by Joni Mitchell with the sax of Wayne Shorter, who has worked with both Mitchell and Hancock. The smoky voice of Norah Jones and Shorter’s sinewy soprano slalom seductively through “Court and Spark,” while the pianist waxes lyrical on a tender “Both Sides Now.” Mitchell even adds her own singular phrasing to “The Tea Leaf Prophecy.”