Henri Paul Julien Dutilleux was a French composer of late 20th-century classical music. Among the leading French composers of his time, his work was rooted in the Impressionistic style of Debussy and Ravel, but in an idiosyncratic, individual style. Among his best known works are his early Flute Sonatine and Piano Sonata; concertos for cello, Tout un monde lointain... and violin, L'arbre des songes ; a string quartet known as Ainsi la nuit ; and two symphonies: No. 1 (1951) and No. 2 Le Double (1959).

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.