Dewey of The Hidden Side of the Leaf began the read-a-thons. She passed away quite suddenly (at least suddenly to the book blogging community) last November 2008, which is why the read-a-thon has been renamed in her honour.
While I did not know Dewey, I can see that her book loving spirit has been kept alive through read-a-thons like these. Thanks to Dewey's past efforts the book blogging community comes together twice a year to share in the love of books and blogging.