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.
Expiration of Copyrights. Copyrights do not last forever. The life of a copyright for creative material produced or published after 1977 is the life of the author plus 70 years. In other words, the copyright lasts for as long as the author remains alive and for an additional 70 years after the author dies.