Most of Dr. Seuss’s books had only his hand lettering on the cover, but this title uses a font. The letters appear to match Cambra on page 18 of the “Alphabet Thesaurus, Vol. 2” published by Photo-Lettering, Inc. New Century Schoolbook was used for the interior of this and many of the other first edition Dr. Seuss books.
Update: Stuart Sandler informs me that this is actually Filmotype Major, released as a photocompositor font in 1951. It was recently revived by Rian Hughes and released under the new digital incarnation of the Filmotype foundry owned by Sandler.