[1][2] The composition process is likely to have started as early as 1936, as Bernstein was able to play it in part at a reception for Dimitri Mitropoulos in January 1937.
[4][3] Bernstein's Piano Sonata is divided into two untitled movements with a total approximate duration of 15 minutes.
It starts out with a "Presto" cadenza with one melodic line and moves on to a "Molto moderato" subsection in which one of the main themes is presented.
This section is in an unchanging 88 and features a segment in bars 46 and 47 where the pianist is asked to play a wide range of white notes with their arms.
In fact, Bernstein specifies that it must be played legato, "wandering", without rhythm or phrasing, and that "the time values indicated in this cadenza are only approximate to what is psychologically correct.