public static Comparator<Book> sortByTitle = (Book book1, Book book2) -> {
        String bookTitle1 = book1.getTitle().toLowerCase();
        if (bookTitle1.substring(0, 4).equals("the ")) {
            bookTitle1 = bookTitle1.substring(4, bookTitle1.length());
        }

        String bookTitle2 = book2.getTitle().toLowerCase();
        if (bookTitle2.substring(0, 4).equals("the ")) {
            bookTitle2 = bookTitle2.substring(4, bookTitle2.length());
        }

        return bookTitle1.compareTo(bookTitle2);
    };