This five CD box set comes with liner notes by Ashley Kahn (no less) and is in essence a celebration of the close working relationship shared by Liebman and Beirach that dates back some 50 years to when both were growing up in post-war Brooklyn. They first recorded together as members of Liebman's Lookout Farm, which debuted on ECM in 1973 and gradually mutated into the Dave Liebman Quintet with Randy Brecker on trumpet and finally, in the 1980s, into Quest, an inside/outside quartet that could go anywhere and seemingly do anything.

In later years, Beirach took up a teaching post in Leipzig while Liebman travelled the world as founder and artistic director of the International Association of Schools of Jazz. Both are exemplars of the jazz tradition, with a masterful command of both inside and outside techniques. This collection of recordings – CD1 Empathy: Liebman and Beirach duos; CD2 Lifelines: Liebman and Beirach plus Jack DeJohnette; CD3: Aural Landscapes: Liebman solo; CD4 Heart of Darkness: Beirach solo; and CD5: Liebman and Beirach with Volxem and Leo Henrichs – comprises about five hours of intense, concentrated music-making. There's more than a hundred years of collective musical knowledge distilled here, for example, Beirach has studied the techniques of Schoenberg, Alban Berg and Anton Weber and the Darmstadt School, so when freedom and atonality emerges it is handled with a depth of knowledge and profundity that seldom surfaces in jazz.

Throughout, the duo show how they can take a kernel of a musical idea and develop and burnish it into a spontaneously conceived work that grows and evolves with organic logic. Both players have never quite been given the due for the masters they are; maybe this set will tip the scales a little more in their favour, but don't hold your breath.