Fred Gwynne died from cancer in 1993, he was 66 years old. He was an actor, an artist, a musician an author and an illustrator. His film and TV roles are discussed in detail on many different TV and movie websites. The focus here (of course) is on the books he wrote and illustrated. The following is a biblio checklist of his books, the books listed are the first appearance of each title, later printings and paperback editions are not listed. The main reference source for this list is The Library of Congress Card Catalog.
BEST IN SHOW. NY: Dutton 1958. [1st ed.] unpaged (chiefly illus.) 26 cm. Note: I was lucky enough to have a copy of this book in the early 90's. The black and white illustrations were brilliant and quite different from the cartoon quality of his later color illustrations. However, his love for jokes and visual humor was already very apparent.
WHAT'S NUDE? Illus. by Fred Gwynne; photos, by Peter Basch. With an introduction by Nathaniel Benchley. New York, I. Obolensky . unpaged (chiefly illus.) 24 cm. (I'm guessing this probably wasn't a children's book :-)
THE BATTLE OF THE FROGS AND THE MICE A Homeric Tale by George W. Martin. New York, Dodd, Mead . 55 p. illus. 22 cm. A sample of this book showing an example of some of Gwynne's stunning black and white illustrations is available courtesy of the author.
GOD'S FIRST WORLD. New York, Harper & Row . [1st ed.]  p. illus. 21 x 26 cm. I have no plot or illustration information on this title.
THE KING WHO RAINED. New York, Windmill Books   p. col. illus. 32 cm. ISBN: 0878070087.
THE STORY OF ICK. New York, Windmill Books   p. illus. 22 x 27 cm. ISBN: 0878070133.
ICK'S ABC. New York, Windmill Books   p. illus. 22 x 27 cm. ISBN: 0878070133.
A CHOCOLATE MOOSE FOR DINNER. New York : Windmill Books, 1976.  p. : col. ill. ; 29 cm. 1st ed. ISBN: 0525615458.
SIXTEEN HAND HORSE. New York : Windmill/Wanderer Books, c1980.  p. : col. ill. ; 29 cm. ISBN: 0671961004.
THE KING'S TROUSERS by Robert Kraus. Illustrated by Fred Gwynne. New York : Windmill Books, c1981.  p. : col. ill. ; 31 cm. (no isbn listed in LOC).
A LITTLE PIGEON TOAD. New York : Simon and Schuster Books for Young Readers, c1988.  p. : all col. ill. ; 29 cm. ISBN: 0671666592.
PONDLARKER. New York : Simon and Schuster Books for Young Readers, c1990.  p. : col. ill. ; 21 x 25 cm. ISBN: 0671708465.
EASY TO SEE WHY. New York : Simon & Schuster Books for Young Readers, 1993. 1 v. (unpaged) : col. ill. ; 21 x 25 cm. This book was a reformatted (rectangular instead of square) and color version of his first book BEST IN SHOW. Neither the copyright page or the Library of Congress entry acknowledges this fact. The original edition was illustrated in black and white, printed on high quality, slightly glossy paper and was a very nicely bound flatback book. The reprint was rectangular, the color illustrations muddy and had a wrap around pictorial dust jacket that gave away the punchline of the story before you even opened the book.
Any corrections or additional information on Fred Gwynne's books or artwork would be greatly appreciated. Also, I welcome any information regarding his black and white illustrations or original art. Clarification as to whether WHAT'S NUDE and GOD'S NEW WORLD were illustrated in black and white and also whether or not GOD'S NEW WORLD was a children's book would help complete this list.
As always, thanks for reading,