Prokofiev had a lifelong love of the sonata form. Ever since learning the basic rules during his childhood years, he strove to master them; … In 1941, describing his Sonatinas op. 54 (1931), he remarked, I liked the idea of writing a simple work in such a superior form as sonata. One can learn a lot about the composer's growth by tracing his progress from the early sonatas, which cautiously dare to bend the textbook rules, to the masterful treatment of the form in his late works.

Prokofiev's piano sonatas : a guide for the listener and the performer (2008) - Preface