Hitchhikers Guide To The Galaxy. Sequels Already Suggested.

Not rocket science to figure out that since it's the first of many books, it could be the first of many films. Disney is apparently considering the option to do more. Theres a piece which embelishes this here. I would suggest that since there's no talk of anyone having signed to do any more (at this point) that the speculation is only founded on the amount of material available, and that the original contract to produce the film would more than likely have contained the option for more films on other books in an automatic attempt to cover the possibility that the first film does really well. As time goes on, and more countries show the film, we will see if any more develops from this.