CreateBook creates a new book.

DeleteBook deletes a book by ID.

GetAllBooks gets all books.

GetBookByID gets a book by ID.

GetBooksSortedByCostAscending retrieves a sorted list of books ordered by cost in ascending order.

GetBooksSortedByCostDescending retrieves a sorted list of books ordered by cost in descending order.

SearchBooksByTitle searches for books by title.

UpdateBook updates a book by ID.