Penguin Books have started doing their version of Mashups. They take a classic text - which is out of copyright. That text would be available FREE as an eBook at Project Gutenberg. But they 'enrich' the text by adding introduction, notes, associated materials, filmography, and so on. Then they can justifiably claim that their version has 'added value', and offer it for sale. Their version of Mary Shelley's 'Frankenstein' contains
* How to Read Frankenstein
* Appendix IV: From Plato's Symposium
* Frankenstein Chronology
* Nineteenth-Century Reviews of Frankenstein
* Frankenstein Filmography
* Suggested Further Reading
Our versions of the classics contain plot summaries, character lists, video clips, critical commentary, further reading, and links to eBooks - and they're FREE.