Imagine you want to learn about how to help people who are sick or injured. There are lots and lots of ways that people have figured out to do this over the years, and it can be really hard to remember them all or know which ones are the best to use.
So, imagine someone wrote a book that has all of these different ways to help people in it - like a really big book that has all of the best ideas and tips for making people feel better. But, because it's such a big book with so many ideas, they split it up into seven smaller books.
Each of the seven books focuses on a different part of the body, like the chest or the stomach or the head. And in each book, there are lots of different ideas for how to help people who have problems with that part of their body.
So, if you ever need to know how to help someone who's feeling sick or hurt, you can use these books to look up ideas and tips for how to do that. It's like having a really big instruction manual for helping people feel better!