1. Why did Sultan send his agents to all parts of the East?
2. They searched the booksellers's shops at Cairo, Damascus and Baghdad for rare volumes for Sultan's library.
3. When the book was not to be bought at any price, he would have it copied or heard.
4. When the author had not yet written the book and was only in his mind, he would have heard it.
5. He had gathered no fewer than four hundred thousand books.
6. It was difficult to collect so many books in those days because;
(a) Printing was unknown
(b) Every copy had to be painfully copied in the fine clear hand of the professional copyist.