The theme of collaboration weaves a tidy thread through "Open Letter," the newest release from Brooklyn-based trombonist Brian Drye and his baritone saxophonist father Howard Drye. The enormous ampersand that dominates the album cover gives way, when opened, to a sparse line drawing of the two Dryes, facing each other, ostensibly deep in communication about the music. The collaborative efforts don't start and end with the artwork; this double CD features ten original compositions, five by the elder Drye and five by the younger, each written to honor an influence from the composer's musical journey. The Dryes are joined by a bevy of top-flight musicians who provide the alchemy that turns this meeting of the minds and notes into something that is far greater than the sum of its tunes. In addition to the Dryes, "Open Letter" features Jeff Hermanson on trumpet and fluegelhorn, Mike McGinnis (Brian's bandmate in the excellent chamber ensemble The Four Bags) on winds, Dan Fabricatore on bass, and Vinnie Sperrazza at the drum kit.