Karol Rathaus, an émigré composer, wrote this piece with the rhythmic vitality and acerbic harmonic language characteristic of the early twentieth-century modernism. It is a bold, percussive take on the traditional Ballade form.
The performer must master precise articulation and rhythmic drive to overcome the piece's complex modern textures.
Comparable difficulty and character — good candidates for what to learn next.
Ballade (Op. 40) is rated Henle level 6 of 9 — advanced repertoire, roughly ABRSM grades 7–8. In the RCM system it corresponds to about level 9.
You should be comfortable at Henle level 6 — meaning you can already play level 5–6 pieces cleanly. Learning it one level early is possible as a stretch piece, but more than that usually leads to months of frustration.
A typical performance of Ballade (Op. 40) lasts about 7 minutes.
Ballade (Op. 40) is available as free public-domain sheet music on IMSLP — the score is linked directly from this page.
Pieces at a comparable difficulty and character include Boléro by Maurice Ravel, Piano Sonata No. 8 'Pathétique' by Ludwig van Beethoven, Prelude in G minor, No. 5 by Sergei Rachmaninoff — see the full similar-pieces list on this page.