Before each story there is a brief introduction that introduces us to the world that the author has written the story about. The only one that I have already read is Stephen King's Dark Tower. I have only read the first few books in the series but that made Stephen King's story my favorite as we travel with Roland on his journey and encounter what we can only describe as a form of vampire.
I have Card's books on my TBR mountain so his story was a nice introduction to his work and was enjoyable. Kind of makes me think of an American version of DiscWorld. lol
I also enjoyed Feist's Riftwar story as I also have some of his books on my TBR pile.
I have to admit that I did not read Silverberg's story as the introduction did not lead me to believe that I would care for the series.
Overall though a nice read with some great introductions, or additions to some wonderful series.
First of the trilogy of anthologies. Stephen King contributes a Dark Tower story, Robert Silverberg contributes a Majipoor story, Orson Scott Card does an Alvin Maker story and Raymond E. Feist does a story set in the Riftwar universe. If you have a favorite series, go for it.