Composed in 1970, the Sonata bears the sub-title "He Epikureia Hedone", or "concerning the rapture of Epicurus", a Greek philosopher born in 341 B.C., six years after Plato's death. Written in one continuous flow, the work was inspired by the philosophy of Epicurus.

The Sonata opens with an introduction, built from fragments of some of the main themes of the work. The principal subject of the Allegro follows immediately in A flat. It is 20 bars long and falls into four phrases; in the first two the subject is presented in unison, in the third and fourth it is accompanied by a second voice part. A linking passage leads to the repetition of the principal subject, fully harmonised in F. Then follow the four second subjects in various related keys, three of which bear a dance-like character. After a bridge passage, reminiscent of the introduction, comes a slow movement with three distinct sections, all of which are subsequently repeated in varied presentation; the development and recapitulation of the allegro exposition then follows, and the work ends with a coda.

The principal allegro subject is developed from a melody, derived from classical Greek music, and the idiom is based upon classical Greek scales. It is dedicated in friendship and high esteem to Ronald Stevenson.