This book had two different titles. The first book was titled Little PeeWee Or, Now Open the Box. It was published in 1947. The second title was Little PeeWee, The Circus Dog Or, Now Open the Box. It was published in 1948. I am sure this is the story . It is available on ebay right now. Good luck!
My 1st memory was looking at and sharing my favorite golden book with a friend before we moved to another state. I had to be about 4 yrs old then, so since i was born in 1957, i guess it was published around then. It was the story of the worlds tiniest dog and a man had him jump out of a box in a circus. The man had a top hat and i think the dog was black & white, spotted. I never knew there was a way to find this out, although i've told a few people over the years. I saw it once in a doctor's office when I was in high school, & was tempted to take it, though i didn't.