Lets talk about the Hillary book then.
Hillary paid a ghost writer to write book for her and gave her no credit.
Later it was found the book was very close to a children's book of the same name. And that she likely copied that book without permission.
The books were used to collect money from donors that could not legally give money to the president.
This is how it is done in DC. People wanting to give money would buy truck loads of books.
Every senator who is on the take has a book this is how they legally take bribes. People wanting favors just buy truck loads books. They throw away the books its just a money transfer.
No senator or president should ever be allowed to sell books or any product while in office.