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.
For works created but not published or registered by January 1, 1978, copyright lasts for a period of 70 years after the author's death (or at least through December 31, 2002). For works published on or before December 31, 2002, the term of copyright lasts through December 31, 2047.