Dr SeussMog

Geisel was first motivated to become an illustrator during art classes at school in the early 1900s, when a teacher rallied against him "fooling around" with whimsical, cartoon-type drawings. "The teacher wanted me to draw the world as it is; I wanted to draw things as I saw them," he later said.

His talent for witty cartoons flourished during his years at Darmouth College, and later at Oxford, but his first attempts to get children's books published were met with continual rejections from around 30 publishers. Some felt his use of colour - including reds and "about seventeen different blues" was impractical in terms of cost, and others objected that his stories "had no moral message."

"What's wrong with kids having fun reading without being preached at!" Geisel complained at the time. Eventually, his first book, And to Think That I Saw It on Mulberry Street, was published - but only because of a chance encounter with a publisher friend, when he was on his way home to destroy the manuscript. It promptly sold 10,000 copies - easily proving that as Geisel loved illustrating for children, they too loved his illustrations.

The Cat in the Hat, Geisel's most famous work, was published in 1957 and came about in response to flailing literary levels among first graders in the US at the time - and a challenge from a publisher who told Geisel to "bring back a book children can't put down." The formula of the book, based on tall anthropomorphic cat with verse rhymes, was radically different from anything else around then. According to Geisel, "It is the book I'm proudest of because it had something to do with the death of the Dick and Jane primers."

Quentin Blake

How to become a children's book illustrator