Rachmaninoff wrote his 3rd Piano Concerto in 1909 during a summer vacation on his family's estate in Russia, where he wrote many of his works before he left Russia in 1917. The work has never been as popular as his 2nd piano concerto, but Rachmaninoff himself preferred the 3rd as he said the 2nd was more uncomfortable to play.
There has not been a great deal of agreement with Rachmaninoff's comment as the 3rd Piano Concerto's reputation persists among other pianists as one of the most difficult in the entire repertoire. All of his works for piano and orchestra are difficult technically and with Rachmaninoff being one of the top virtuoso performers of the 20th century, that is no surprise. But there is more to it than that. Part of the difficulty is that the soloist has very few measures where the piano is not contributing either as soloist or accompanist. Rachmaninoff approved some optional cuts in the work to help shorten it and make it more popular, but these cuts are seldom taken in modern performances. Without the cuts the work lasts roughly 40 minutes, a real test for a pianist's stamina and alertness.
The 3rd Piano Concerto was premiered in New York late in 1909 with the New York Symphony Society, and was repeated a few weeks later with Rachmaninoff again the soloist and Gustav Mahler conducting. The concerto was dedicated to the Polish-American virtuoso pianist Josef Hofmann, but he never performed it in public. The concerto is in three movements:
I. Allegro ma non tanto - The first movement begins with the orchestra playing two bars of gently throbbing material and the piano enters with a simple theme played in both hands an octave apart. This theme and parts of it occur throughout the concerto:
II. Intermezzo: Adagio - The orchestra plays a melancholy theme in F-sharp minor for an extended time in the beginning of this movement, the longest section without piano participation in the entire concerto. Shortly after the piano enters the second theme in a major key is played by the soloist. The piano takes up the first theme, and piano and orchestra develop it. The second theme is heard once again and varied. Among the variations is a waltz with the orchestra carrying the thematic material while the piano plays a glittering accompaniment. The orchestra then plays an interlude without piano that is reminiscent of the main theme of the first movement and then harks back to the introduction of the second movement. The piano changes the mood with a short solo, and then soloist and orchestra join together to lead into the last movement without pause.
III. Finale: Alla breve - There are two vigorous themes in this movement that are heard one after the other in the beginning. After these themes are presented, the second theme of the first movement is combined with the initial theme of this movement for what at first appears to the ear as new material. The main theme of the first movement then appears in a varied form in the cellos and is hinted at in the piano, after which the second theme from the first movement makes another appearance. After some transitional material, the two themes of this movement reappear, recognizable but in different clothes. Then Rachmaninoff switches keys to D major, and the music gets more and more animated. A new theme in the new major key and as it broadens it rises into the stratosphere of Romantic expression, something that Rachmaninoff was a master of. The music quickens again and rushes to a glorious ending.