Pictured below are some of the hardest-to-find dust jackets in the collection, based on almost 30 or so years of hunting:
Best Cartoons of the Year (1942): The is the jacket from the first volume of the 30-year series edited by Lawrence Lariar. I've seen only four copies of this jacket. The size is about 20% larger than the volumes published in subsequent years.
Addams and Evil (1947): If you thought that the dust jacket for his first book, "Drawn and Quartered" (1942) was the scarcest jacket, think again. It's the one pictured below, from the first printing. Subsequent printings appeared in a slightly smaller format.
Adventures at Golf: Virtually impossible to find a copy in its original jacket. Trivia: the book's cover bears no resemblance to its jacket.
The Ruling Clawss: Writing under the pseudonym "A. Redfield," Syd Hoff's "The Ruling Clawss" is filled with devastating social commentary cartoons. This is the only jacket I've ever seen for this book. The only one.
Favorites: Very, very difficult to find the jacket for Peter Arno's 1932 "Favorites." I've seen four others in my lifetime.
The Fourth New Yorker Album: Did you think that the first New Yorker album of cartoons, from 1928, had the most difficult-to-find jacket? Nope. It's the Fourth Album. I've seen two.
The Fifth New Yorker Album: Almost as difficult to find as the Fourth. I've seen three. Good luck!
Webster's Poker Book: This book was published in two forms: one with, and one without, a "drawer" affixed to the back cover. The one with the drawer contained IOUs, invitations, and cut-out poker chips. I've seen only one copy of the jacket to this version and only three for the non-drawer version.
The Timid Soul: Very tough to find a copy of the jacket to this volume of Webster's cartoons from 1931.
The Little King: Pictured below is the jacket from the 1933 first edition. (There was a later one, cheaply produced, in 1945.) Not as rare as the other jackets pictured here, but still not easy to find.