A friend gave me a small stack of books that were published around that period, including a Tolstoi, George Eliot, Stevenson, etc. There is a version of Alice in Wonderland from 1905 that is written in primarily one syllable words (published, I might add, despite the fact that the copyright didn't expire until 1910). What I've found the most fascinating in the bunch, however, misses your time period.
There is a series of pamphlets put out by the YWCA in 1916, during WWI. Each pamphlet was written by a different author, many big names for the time, including President Woodrow Wilson's daughter, and several Suffragettes. They are a fascinating window into what the world was like for women in that time period. If you're looking for the 'voice' of the era, maybe magazines (often available in microfilm) or something akin to these pamphlets would be excellent sources. If you're looking for popular novels of the day, everyone else has excellent suggestions.
-- Joanna