Question: what old books are worth money?
Answer: Harry Potter and the Philosopher's Stone (1997), J.K. Rowling.
The Cat in the Hat (1957) Dr. ... 
The Hound of the Baskervilles (1902), Arthur Conan Doyle.
The Bible (1600 – 1630)
The Jungle Book and The Second Jungle Book (1894-1895) Rudyard Kipling: