A few of these are duplicates that I got later but most of them are from my childhood.
Below are the front and backs of some of the oldest of the books. While they aren't 1st editions, they're from the mid-1960's, these are some of the first books in the series that ran until 1991.
This is the very first book.
This is an exception, not being a Fawcett Crest publication but it's one of my favorites.