Though he won't turn 60 till next year, Monty Alexander is already one of the grand old men of piano jazz. It's been nearly five decades since he cut his first hits in his native Jamaica, at age 14, and 40 years since Frank Sinatra heard him in Vegas and gave his stamp of approval. Soon after, in the mid-60s, bassist Ray Brown took Alexander under his wing, providing both platform and imprimatur for the young pianist's kaleidoscopic technique and soulful swing. Not till the 80s did Alexander begin to plumb the undercurrents of reggae (and of mento, the rural folk style from which it sprang) that till then had only occasionally surfaced in his playing: over the next 20 years or so he recorded with such legendary Jamaicans as guitarist Ernest Ranglin and the rhythm machine of Sly Dunbar and Robbie Shakespeare. Nowadays he seems less intrigued with fusing jazz and reggae than with weaving together all the disparate threads of his music. He tried it first on last year's My America (Telarc), an eclectic assortment of standards--many of them inflected with island beats--that never really jelled. But a similar box-of-chocolates approach succeeds entirely on Alexander's new Impressions in Blue (Telarc), which consists of four short, distinct segments, each devoted to one of the flavors in his style: classical music (Gershwin and Rodrigo); the compositions of Duke Ellington; the performances of Nat "King" Cole's 1940s trio; and the West Indian melodies and rhythms of his youth. Alexander's name doesn't often leap out when people talk about jazz piano, but I've heard several performances that left me wondering why: in a club setting, his combination of ferocious jazz swing and Jamaican roots can pack more punch than anything they've got behind the bar. He plays here in a quartet with hand percussionist Robert Thomas Jr. and the rhythm section from Impressions in Blue, bassist Hassan Shakur and drummer Mark Taylor. Tuesday, September 16, through Thursday, September 18, 8 and 10 PM, Friday and Saturday, September 19 and 20, 9 and 11 PM, and Sunday, September 21, 4, 8, and 10 PM, Jazz Showcase, 59 W. Grand; 312-670-2473.