On the subject of rejections, something Snoopy is very well acquainted with, Jack Canfield writes:
"Dr Seuss's first children's book, And To Think That I Saw It On Mulberry Street, was rejected by twenty-seven publishers.
Margaret Mitchell's classic Gone With The Wind was turned down by more than twenty-five publishers.
Jack London received six hundred rejection slips before he sold his first story."
And of course, as ever, I am leaving the best last:
"Eight years after his novel Steps won the National Book Award, Jerzy Kosinski permitted a writer to change his name and the title and send a manuscript of the novel to thirteen agents and fourteen publishers to test the plight of new writers. They all rejected it, including Random House, which had published it."