Tout un monde lointain... is a concertante work for cello and orchestra composed by Henri Dutilleux between 1967 and 1970 for Mstislav Rostropovich. It is considered one of the most important 20th-century additions to the cello repertoire and several major cellists have recorded it. Despite the fact that the score does not state that it is a cello concerto, Tout un monde lointain... has always been considered as such.

The cello ( CHEL-oh), or violoncello ( VY-ə-lən-CHEL-oh, Italian pronunciation: [vjolonˈtʃɛllo]), is a bowed (sometimes plucked and occasionally hit) string instrument of the violin family. Its four strings are usually tuned in perfect fifths: from low to high, C2, G2, D3 and A3. The viola's four strings are each an octave higher. Music for the cello is generally written in the bass clef, with tenor clef, and treble clef used for higher-range passages.