Debussy wanted to distance himself from what he considered the emotional excess of the Romantics and instead wanted to write music that, through sound, created an ambience similar to that of the Impressionist painters and Symbolist poets of his day.
All books initially copyrighted in the US from 1964 through 1977 have had their copyrights automatically renewed (by law) and the copyrights are still in force. The initial copyright term was 28 years; the renewal was for 67 more years.
See Challenge to Constitutionality.) Thus, if a work was published in 1922 or earlier, it is now in the public domain. Works that were published between 1923 and 1963 have a 95-year term, provided the copyright was formally renewed in the 28th year. Works published between 1964 and 1977 have a flat 95-year term.