Why use two names when defining a struct? (C)

Question

Hi, so I was wondering why when, for example, in the code at the end of the message, they define a structure named "book" by using:

typedef struct Books {
...
} book;

instead of using

typedef struct {
...
} book;

What's the point of writing "Books" after typedef struct?
Thanks in advance.

https://www.tutorialspoint.com/cprogramming/c_typedef.htm

Answer 1

Structs are custom data types.
"Books" is the name of said data type.
"book" is the name of a variable of type Books.