Metheny/Mehldau Quartet is a jazz album released in 2007 by Nonesuch Records, and is a collaboration album between guitarist/composer Pat Metheny, and jazz pianist Brad Mehldau. The first disc, Metheny/Mehldau, was released in 2006, and contains mostly duet recordings with the exception of two tracks. On this album, however, Mehldau's two trio men, drummer Jeff Ballard and bassist Larry Grenadier are much more present, given the title of the album.