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.
In some other countries, including Canada, copyright term is life plus 50 years, and in those countries C.S. Lewis, Aldous Huxley, Robert Frost, Jean Cocteau, and the famous poet Sylvia Path, who all died in 1963, enter the public domain in 2014.