Pianist and jazz restructuralist Misha Mengelberg has received much acclaim for everything from his solo performances to his leadership of the Dutch ICP Orchestra, but the small-ensemble recordings he began making in the U.S. during the '90s are perhaps the best places to begin investigating his wonderfully offbeat charms. Four in One, recorded in September 2000 and subsequently released in "Super Audio CD" format by the Songlines label, is an album with particularly wide-ranging appeal, satisfying for listeners with tastes ranging from the avant-garde to more traditional post-bop, and certainly anyone interested in the commonality between Mengelberg and one of his primary influences, Thelonious Monk. The half-American, half-Dutch quartet (shades of Gerry Hemingway), featuring Mengelberg's longtime co-conspirator Han Bennink on drums and New Yorkers Dave Douglas on trumpet and Brad Jones on bass, is a perfectly compatible foursome. A few scattered free rhythmic episodes aside, Bennink is in nearly straight-ahead mode throughout the disc, curbing the subversions and hijinks he often throws into the ICP mix in favor of a consistent, highly charged swing. Jones' walking basslines push the ensemble through the chord changes at a sprightly pace, providing a foundation that effectively balances the freewheeling solo flights from Mengelberg and Douglas. And those solos are freewheeling indeed. Mengelberg's idiosyncratic sense of timing, phrasing, and melody are on full display beginning with the opening track, his up-tempo boppish "Hypochristmutreefuzz," originally from the very first recording on which Mengelberg appeared (and a very early one for Bennink too) back in 1964, Eric Dolphy's Last Date. On this new version of the tune, Mengelberg doesn't attack the keyboard with as much relish as on the take from over 35 years earlier, but rather in a more personal style with a completely elastic sense of time; he inserts fragments of the melody here and there in a seemingly careless fashion that somehow makes perfect sense. If it's possible to conceive the idea of rigorous nonchalance, Mengelberg would be its embodiment. And he ends the solo with a musical shrug, as if to say, "OK, that's enough, I'm done, now it's your turn, Dave." As expected, Douglas doesn't disappoint. His timing here is more spot-on than Mengelberg's, so the trumpeter relies on his continually expanding arsenal of techniques to offer up a slippery solo filled with chromatic runs, wide-interval leaps, and an escalating urgency that ups the energy level right through into the tune's slam-bang finish. It's another great Douglas performance that stands up well in the inevitable comparison to the Dolphy bass clarinet solo on the Last Date track. Whether in soloist, accompanist, or ensemble mode, all four musicians shine on the diverse selection of tunes across the entire disc, a number of which revisit Mengelberg compositions from various phases of his career, including not only "Hypochristmutreefuzz" but also "Reef" from Dutch Masters and "Kwela P'Kwana" from the ICP disc Bospaadje Konijnehol II. The somewhat melancholy "Kneebus," also from Dutch Masters, reveals Douglas' debt to Mengelberg in some of his own work with Tiny Bell Trio and Charms of the Night Sky. But as for a connection between musicians, the strongest exhibited here involves Mengelberg and Monk. The three Monk covers -- "Monk's Mood," "Criss Cross," and the title track -- fit in so well that one scarcely realizes where the Mengelberg tunes end and the Monk tunes begin. Yet, as always, Mengelberg projects an identity all his own, as he effortlessly redefines the possibilities of jazz with another tossed-off shrug.