Adapting anything from one media to a screenplay is a matter of three distinct possibilties.
1) Straight adapation retaining as faithful as possible without deviating from the original author’s story, and this includes characters and language.
2) ‘Based on’, similar to the above but the screenwriter may feel the original story does not lend well to adaption and makes modifications in order that a screenplay adaption can occur.. John August’s BIG FISH screenplay comes into this category.
3) Using the original story and characters but writing a completly different story and or plot, adding and or removing characters and adding and removing essential dialogue so the resulting screenplay bares no relaton at all the the original source material.
You don’t need to own the rights of a literary work to adapt it to write a screenplay partly if the exercise if for eduational purposes.
Most screenwriting courses teach writing scripts based on literary works where the copyright has expired 50 years after the death of the author. Edgar Alan Poe, Charles Dickens and similar authors come to mind here.
You can for example, download these literary works in ASCII text format from Project Gutenberg as ‘e-book’ format for FREE at
http://www.gutenberg.org/Project Gutenberg actually possesses the works of the two authors mentioned above which you can downlolad. There are many more. If you visit Project Gutenberg’s web site you find all manner of written works which are out of copyright and could be used to produce a screenplay adaption from.
Some countries or territories as they are know in the media world, do have different copyright laws so if you go down this path to attempt an adaption with the view of submitting the screenplay to a professional body then make sure the copyright of that literary work for your country has expired.
Some literary works copyrights are re-newed by estates of the authors to prepetuate earned monies from rights for dependants and relatives of those authors.. Others may have been bequethed through a last will and testiment of the author to an organisation or charity so any monies earned is paid to that entity.
A good example is the copyright status of Peter Pan the play and children’s book written by J.M. Barrie.
Copyright status
The copyright status of Peter Pan varies from one jurisdiction to another, and is disputed in at least one of them. The question is complicated somewhat by the various versions in which the story has been published. For example, elements introduced in the earliest versions of the story by Barrie may be in public domain in a given jurisdiction, but elements introduced in later editions or adaptations might not. For example, Disney holds the copyright for the character designs, songs, etc. introduced in the 1953 animated film, but not for the characters themselves.
European Union
Great Ormond Street Hospital (to which Barrie assigned the copyright as a gift before his death) claims full copyright in the European Union until the end of 2007. In the 1990s, the term of copyrights was standardised throughout the EU (see Directive on harmonising the term of copyright protection) to extend 70 years after the creator's death. Although Peter Pan was considered public domain in some jurisdictions at that time, this provision placed it back under copyright protection.
United Kingdom
The U.K. copyright for Peter Pan originally expired at the end of 1987 (50 years after Barrie's death), but was reestablished through 2007 by the European Union directive. Additionally, in 1988 the government had enacted a perpetual extension of some of the rights to the work, entitling the hospital to royalties for any performance or publication of the work. This is not a true perpetual copyright, however, as it does not grant the hospital creative control nor the right to refuse permission. Nor does it cover the Peter Pan sections of The Little White Bird, which pre-dates the play. The exact phrasing is in section 301 of the Copyright, Designs and Patents Act 1988:
301. The provisions of Schedule 6 have effect for conferring on trustees for the benefit of the Hospital for Sick Children, Great Ormond Street, London, a right to a royalty in respect of the public performance, commercial publication, broadcasting or inclusion in a cable programme service of the play 'Peter Pan' by Sir James Matthew Barrie, or of any adaptation of that work, notwithstanding that copyright in the work expired on 31 December 1987.
United States
The conversion of U.S. copyright terms from a fixed number of years following publication, to an extending number of years following the creator's death, has introduced confusion over Peter Pan's copyright status. Great Ormond Street Hospital claims that U.S. legislation effective in 1978 and again in 1998 extended their copyright until 2023. Their claim is based on the copyright for the play script for Peter Pan, which was not published until 1928. By then, the character of Peter Pan had appeared in three previously published books, the copyrights of which have since expired.
GOSH's claim is contested by various parties, including Disney, who had cooperated with the hospital previously, but in 2004 published Dave Barry's and Ridley Pearson's Peter and the Starcatchers without permission or royalty payments. The Library of Congress catalog states that the original edition of Peter and Wendy was published in 1911, and Disney asserts that that material, like any other work published before 1923, was already in the public domain at the time of these extensions, and was therefore ineligible to be extended.
A dispute between the hospital and writer J.E. Somma over the U.S. publication of her sequel After the Rain, was settled out of court in March 2005. GOSH and Somma issued a joint statement which characterized her novel as "fair use" of the hospital's "U.S. intellectual property rights". Their confidential settlement does not set any legal precedent, however.
Other jurisdictions
The original versions of Peter Pan are in the public domain in Australia and in Canada (where Somma's book was first published without incident).
So to answer your question, by all means adapt a works if you feel confident about it but for commercial purposes you need to own the rights to make a commercial film from your screenplay.
If the copyright has expired by at least 50 years after the author's death then by all means adapt a literary work..
if you do an adaption it's always considered polite to mention the original author and works you adapted from..
BLA BLA BLA
By Me Myself and I
Based on the novel Bla Bla Bla
By That Other Person