Mozart's Sonata for 2 pianos K448

Mozart's only Sonata for Two Pianos, written in 1781, is a fascinating work - not just musically, but also in ways that the composer could never have imagined. Musically it is widely regarded as one of the composer's finest compositions, described by Alfred Einstein thus:

The art with which the two parts are made completely equal, the play of the
dialogue, the delicacy and refinement of the figuration, the feeling for
sonority in the combination and exploitation of the registers of the two
instruments—all these things exhibit such mastery that this apparently
superficial and entertaining work is at the same time one of the most profound
and most mature of all Mozart’s composition

K448 and The Mozart Effect:
http://www.smart-kit.com/s245/how-the-amazing-mozart-k448-can-increase-your-iq-listen-now/