Brad Mehldau is a hard one to figure. He started out as one of a school of new jazz musicians mixing his own compositions with a vocabulary of unexpected songs from the popular arena—most notably Radiohead and Nick Drake songs, before classical-lite reinterpretations rendered such an idea anathema to hipper minds. While clearly informed by post-bop traditions, Mehldau also had one foot in a neo-romantic style, explored most notably on his 1999 solo piano album Elegiac Cycle.

In 2002, Mehldau teamed up with producer Jon Brion to produce Largo, one of the more unusual and brilliant jazz records of the last ten years. Brion was an unexpected choice, being known more for his work on soundtracks (Eternal Sunshine of the Spotless Mind, Punch-Drunk Love), production on albums by Aimee Mann, Fiona Apple, Kanye West, and his own obsessively detailed power-pop. But while Largo pointed to a shared interest in rock—it had more Black Sabbath references than your typical jazz record—Highway Rider unexpectedly marries Mehldau’s classical leanings to Brion’s soundtrack expertise.

The result is split into two distinct halves. The first disc features large ensembles and orchestrations, supplementing Mehldau’s trio with strings, woodwinds, and brass. This part of Highway Rider is something of a mixed bag. Track divisions are nearly seamless, and listeners may be surprised to look over during what seemed to be one shifting movement and discover that they’re now on track five. It works well as a whole, bu the other side of this coin is that few tracks stand out as individual highlights. Other than the knotty repeated phrase at the climax of “Walking the Peaks” or guest star Joshua Redman’s saxophone refrain on “Don’t Be Sad”, few melodies leave a lasting impression. Also, while Largo did not sacrifice immediacy in its pursuit of novel arrangements or production techniques, the orchestral nature of Highway Rider necessarily hampers the spontaneity that one associates with jazz performed by smaller ensembles. As a result, Highway Rider‘s first impression is of a slow, quiet experiment in shifting moods and tonal colors.

Once the listener’s expectations are attuned to the unique nature of Highway Rider, however, it begins to reveal itself as a fascinating and intricate suite. Take, for example, the delicate harmonic development of “John Boy”, which is echoed in the short piano interlude “At the Tollbooth”, which in turn serves as an understated introduction to the title track.

More traditionally jazz-based elements crop up on the second half, though the production is more restrained than one might expect after the genre-busting experiments of Largo and the first disc of this album. Instead, we are left with what is simply an excellent modern jazz record in the post-bop tradition. Joshua Redman returns to take most of the melodies here, though the real star continues to be Mehldau’s lush, harmonically ambiguous piano playing. “Sky Turning Grey (For Elliott Smith)” captures its namesake well, with a loping, melancholic feel, and the pounding, mechanical bassline of “Into the City” provides the record’s most viscerally thrilling moment.

When the orchestra returns for the closing tracks “Always Departing” and “Always Returning”, it reaffirms the suite-like nature of the whole project. At an hour and 45 minutes, Highway Rider defies easy or immediate comprehension, and can be surprisingly difficult to get into for a record so outwardly tonal and pretty. Lurking at the heart of this album, however, is a stunningly original and unpredictable achievement from one of jazz’s great modern practitioners.