The Cat in the Hat (TV special) stopped working on Seuss projects also. DePatie and Freleng were credited together as executive producers, while Jones was credited as producer with Seuss (under his actual name). For the next three Dr. Seuss animation specials, Freleng and Seuss (again using his real name) were credited as producers, although separately. DePatie–Freleng animated a new Cat in the Hat Productions logo for this special, which would be used in the next three specials. The pace and rhyming sequences of several of the songs (particularly "Calculatus Eliminatus") led many to believe that they were composed by Sherman, since they closely resemble his earlier
The Cat in the Hat read, and Spaulding provided Geisel with a similar list. Geisel later told biographers Judith and Neil Morgan that Spaulding had supplied him with a list of 348 words that every six-year-old should know and insisted that the book's vocabulary be limited to 225 words. However, according to Philip Nel, Geisel gave varying numbers in interviews from 1964 to 1969. He variously claimed that he could use between 200 and 250 words from a list of between 300 and 400; the finished book contains 236 different words. Geisel gave varying accounts of how he conceived of "The Cat in the Hat".