This one was originally published in 1931 and it is some of his earliest work. Arguably his most famous work, The Cat in the Hat wasn’t published until 27 years later. Dr. Seuss had 49 books published during his lifetime. That is counting only the books published under the Dr. Seuss name while he was alive. He published others as Theo LeSieg and Rosetta Stone. Also, some other books of his were published posthumously under the Dr. Seuss name. It really is amazing when you think about it.