Perlman, Zukerman
"Bartok: 44 Duos for two violins" (Vinyl)

There isn't an extensive amount written for two violins.  I suppose that's for good reason.  During the mid-20th century, however, there seemed a desire for composers to press into any unexplored orchestrations or instruments in hopes of finding a unique vein to plumb.  (Violists everywhere should be grateful for this attitude.)

Amongst the oddities born from this expedition are Bartok's 44 duos for two violins.   Published in order from least to most difficult, they are each only a few lines of music and can be performed in entirety in approximately 45 minutes.  They were published in a particular order, but Bartok left written instructions for any performers to arrange them according to achieve variety in the performance.

On this recording Itzhak and Pinchas chose to record them in sequential order, from nos. 1 - 44.  One can not really expect a finer recording of these pieces to exist.  It's fun hearing two of the century's great virtuosos playing with each other.