Pianist Mary Lou Williams was one of the true jazz originals. Her beautiful harmonic language and technical virtuosity inspired everyone from Thelonious Monk to Dizzy Gillespie. Virtuoso trumpeter Dave Douglas pays nominal tribute to Williams’ legacy with this collection of solidly written, wonderfully performed tunes. Oddly enough for a purported tribute album, Douglas attacks a list of tunes that were mostly self-penned. The tone and phrasing of Williams’ work is evident in all of the originals, however, showing her influence on Douglas’ musical language. The delightful “Ageless,” in particular, is a wonderful homage to Williams’ ability to build a seemingly simple tune to near-transcendent heights. The backing musicians on Soul on Soul are stunning, with New York City pianist Uri Caine providing some frighteningly dense solos on “Canticle” and “Kyrie.” Reed men Greg Tardy and Chris Speed show equal ability on the saxophone and clarinet, and their wispy phrases on “Moon of the West” provide a wonderful counterpoint to the brassy shine of Douglas’ trumpet work. Many of these performances are, sadly, drawn out too far, losing some of their immediate impact. For this reason the album is overly long and unfocused. Even so, Douglas manages to craft a fine tribute to a true American original.