"The Hunchback of Notre Dame" was the first grown-up novel I read. I have distinct memories of reading it on my parents' king-size bed at age 8. I've also read "Dracula," "The Strange Case of Dr. Jekyll & Mr. Hyde," "Frankenstein," "The Picture of Dorian Gray," and "The Phantom of the Opera." The H.G. Wells books were a lot of fun: "The Invisible Man," "The Island of Dr. Moreau," "Food of the Gods," "First Men in the Moon," "The Time Machine," "War of the Worlds," etc. I've read the H.P. Lovecraft canon and it's fun to track down short stories that served as the basis of horror films like "The Casting of the Runes," and "Carmilla" among so many others. In general, I think a monster movie fan ought to read the source material just to be better informed.