Some fix-ups in their final form are more of a short story cycle or composite novel, rather than a traditional novel with a single main plotline. Examples are Ray Bradbury's The Martian Chronicles, and Isaac Asimov's I, Robot both of which read as a series of short stories which may share plot threads and characters, but which still act as self-contained stories.[5] By contrast, van Vogt's The Weapon Shops of Isher is structured like a continuous novel, although it incorporates material from three previous van Vogt short stories.