Rachmaninoff spent half of his life contemplating his Fourth Piano Concerto, from early sketches penned shortly after completion of the Third Concerto to its final reworking in 1941. Sadly, it has been less popular than his other works for piano and orchestra. More recently, the original version (1926) has been published, leading many to hope that it will receive a fresh hearing.
Read the Research Paper it provides a history of the work, and an analytical comparison of the three versions of Rachmaninoff’s 4th Piano Concerto