Charles Koechlin's orchestral skills were already appreciated during his years at the Conservatoire: in May 1898, Gabriel Fauré asked his young pupil to orchestrate his incidental music for Pelléas et Mélisande Op. 80, including the famous Sicilienne. In 1901, on the recommendation of the same Fauré, he orchestrated Lola Op. 116 (1900) by Camille Saint-Saëns, then, in 1912, the ballet Khamma (1910) by Claude Debussy.
But Koechlin's compositions bear even greater witness to his interest in the rarest instrumentations and the most unexpected sounds, and are full of highly personal discoveries.

Le Traité de l'orchestration was written in Paris in 1941. Divided into four volumes and published posthumously between 1954 and 1959, it contains most of the elements covered in previous treatises on orchestration, from Berlioz's Traité d'instrumentation et d'orchestration (1844), the model of the genre, to works by Gevaert (1885), Rimsky-Korsakov (1912) and Widor (Technique de l'orchestre moderne, 1925).

The work is lavishly illustrated, with the author citing early works by Machaut, Monteverdi, Heinrich Schütz and Johann Sebastian Bach as well as modern scores by Stravinsky, Darius Milhaud and Alfredo Casella. Koechlin also cites his own works, which bear witness to his dual role as composer and teacher.