Chambers was an American writer of the early 1900's. He started as an artist, studying in France and Germany, and later turned to writing. His best known work is probably The King In Yellow, a collection of stories supposedly about a book that drove those who wrote it mad. It's considered an influence on Lovecraft and an early example of Horror.
You can learn more about Chambers at
https://en.wikipedia.org/wiki/Robert_W._Chambers
The King in Yellow is here:
https://www.gutenberg.org/ebooks/8492 (There is a version in LRF format by Dr. Drib here:
https://www.mobileread.com/forums/showthread.php?t=11443
Note that the thread title should be corrected. The title of the book is actually The Slayer of Souls.
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Dennis