The No. 3 (C-minor) etude from Rachmaninoff’s first set of Études-Tableaux, Op. 33 was omitted from the original publication and released posthumously. I haven’t read anything that explains why, but it probably has something to do with one of its melodies making an appearance in his fourth piano concerto, written some fifteen years later. Piano Keys

I guess it’s only expected that, as a composer, you would eventually come to realize that a particular figure might shine a little brighter in a different setting.

Rachmaninoff, Etudes-Tableaux, Op. 33, No. 3
Rachmaninoff, Piano Concerto No. 4, II. Largo

What a melody…

Etude performed by Rustem Hayroudinoff (Chandos). Concerto by Leif Ove Andsnes (EMI Classics).