Wanted to know if Shelly's Frankenstein and Dr. Jekyll and Mr. Hide are up for fair use. Don't know how long it takes before a story loses its copyright allowing for people to make a parody or side story of it without problems. Are these two stories up for use by anyone or can they not be used? Also what's the time duration for a story to become fair use to other authors out there to put their own spin on it?

As far as I understand it, the fair use law is there to protect the authors from anyone else using it to make profit, no matter how old or recent it is. Therefore I think fanfics and other things are allowed, as long as you aren't making profit from them, and clearly outline the original owner of the work. I'm not the expert on this however.

You're confusing fair use with public domain.

Public domain is when it falls out of copyright, which is at least 120 years in most cases (officially at least, unofficially it's anything created before Mickey Mouse)

Fair use is something entirely different and has to do with works currently protected by copyright being used without express permission. It covers things like educational use and parodies but has specific provisions such as that that you may only use the smallest possible piece of the original work as necessary to get the job done. Also if your work that you claim fair use on gains any notoriety at all, your fair use claim will be challenged in a lengthy and expensive court battle.

Both of the books you are thinking about are probably in the public domain, which has nothing to do with Fair Use, as that covers copyrighted materials.

http://copyright.cornell.edu/resources/publicdomain.cfm

Ahh ok thanks for the correction i've been reading too much of that SOPA/PIPA crap and it had me confused.

Thought it was atleast 100 years, but didn't know it could be up to 120 years or so. However, that being said i'm glad I can move forward with my idea without too much worry.