Premiered in 1952 by his wife, pianist Johana Harris, at the Pittsburgh International Contemporary Music Festival, conceived by American composer Roy Harris. Regarding this work, Ginastera stated: "This sonata is written in polytonality and twelve-tone technique. Instead of folk material, it employs rhythms and melodic motifs with an expressive tension that evokes an Argentine feeling." It can be said to be one of Ginastera's representative piano works, vividly combining abstracted Argentine musical elements with contemporary compositional techniques of the time.

First Movement

The first movement, as Ginastera himself explained, "where slurs are not written, play non-legato, and where the volume is loud, play martellato," features a striking contrast between the brave, percussive sound characteristic of the malambo and the simple, lyrical melodies reminiscent of the tranquility of the Pampas. Including such performance techniques, characteristics frequently found in Ginastera's works include parallel thirds, superimposed fourths, and rapidly changing time signatures.

Second Movement

The second movement is constructed using twelve-tone technique from the outset, and its geometric music evokes even a mystical and supernatural atmosphere. A prominent contrast exists between quiet measures with continuous eighth notes incorporating twelve-tone rows and syncopated sections where the melody is sung with full volume. Occasional arpeggios, mimicking guitar playing, and note rows identical to open strings, recall the presence of the gaucho troubadour, the payador. What is faintly visible in the darkness of the Pampas? Is it the dull gleam of a wanted gaucho's dagger, or perhaps a supernatural entity believed in by the indigenous people living in the Pampas? It is a movement where the presence of the twelve-tone technique stimulates various imaginations.

Third Movement

The third movement begins slowly with a series of notes intentionally shifted from the open strings of a guitar, as if responding to the open-string note row played by the left hand in the preceding movement's conclusion. The combination of one quarter note and two eighth notes seen in the melody is reminiscent of the melancholic folk song Triste, but Ginastera further expands it into triplets and quintuplets. The notes accumulated in the coda evoke, as if through perspective, the vast space of the Pampas and the lingering resonance of a plucked guitar.

Fourth Movement

The fourth movement features various elements of the malambo, often found in Ginastera's works, such as intense percussive elements and ostinato. From the time signature "3/8=6/16" indicated in the score, one can discern the characteristics of sesquialtera, which forms the basis of the malambo. Furthermore, it is truly characteristic of Ginastera how the same melodic pattern, such as a single-note melody in the right hand later appearing as a two-hand octave canon, transforms into an ingeniously elaborated expression each time it reappears.