Written in 1945 for the Albeneri Trio and premiered in July 1947 at Tanglewood, this work marks Schnabel's first venture into composing for the genre at the age of 63, despite his extensive experience performing piano trios.

While inheriting a classical structure of three movements (fast-slow-fast), the internal movement of each individual movement is remarkably free, as if intentionally subverting traditional forms and listener expectations. Throughout all movements, it is notable that each part relies on a texture with a strong polyphonic character. According to Schnabel's letters, this compositional approach was adopted as a means to achieve a balance where the piano would not overshadow the other two string parts; however, the linearly unfolding tension, which forms the core compositional method of the music, is also extremely important throughout Schnabel's entire oeuvre.

The first movement, which begins with a floating piano solo, is replete with irregular phrases, accents, and frequent expansions and contractions of temporal units, and despite consisting of relatively few notes, demands a high level of musical skill from the performer. The second movement bears the tempo marking 'Larghetto', but within its leisurely flow, the musical content is extremely light and agile. This is because each individual voice is monologic and rich in expression, resulting in a ceaseless change of color. The third movement begins with a twelve-tone row, but it differs from so-called 'twelve-tone technique' in that this row does not form the structural basis for the entire movement.