The shorter Jewish encyclopedia is like a big book with lots of information about Jewish people, history, and traditions, but someone made a smaller version for people who don't want to read such a long book. It's like how you might have a big toy box with lots of toys, but you might choose to only play with a few of them at a time. The shorter Jewish encyclopedia is for people who only want to learn a little bit about Jewish things, or for people who don't have a lot of time to read. It's a condensed version of the bigger book, like a short and simple summary of all the important things you need to know.