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.
No longer. I'd argue that we are now living in a Golden Age of children's literature. But it's not the first time that children's books as an art-form have blossomed. The First Golden Age, which took off in the 1850s, thanks to the increasing number and status of children, was particularly dominated by five authors.