Chicago: Donald F. Duncan, 1947. First Edition, First Printing. Original wraps. 4 1/2 x 5 1/4 inches. 48 PP. Very Good. Item #4597
Original illustrated guide to Yo-You tricks by Mr. Yo-Yo himself. Duncan held the trademark on the term "yo-yo" from 1932 to 1965. Interestingly, the Supreme Court took his trademark away because he had been so good at marketing the toy, it was no longer called anything else. It wasn't just a brand anymore, it was the toy itself.