Hi there @kristyglas! I found your post through @newbiegames. Here's my contribution, a book by Polly Cameron called "The Dog Who Grew Too Much"

Poking around on the internet, I see that it was published in 1958! It must have been my older sister's book, then passed on to me. I wonder where it is now? I'll have to go look for it next time I visit my mom's house :)