With typical quirky postmodern structure, Amis writes a novel that features a writer and discusses the process of writing a book. One of the main characters is also the author of the book the reader reads, and thus Amis uses a first person narration, as the inital foreword makes clear. Samson Young "can't believe [his] luck," because all he is doing is recording what is happening to those around him rather than having to create a story. However, it is clear that he is an unreliable narrator precisely because he is lacking in imagination and is constrained to writing what happens as it happens, rather than being able to know how the novel ends up. Note what he says:
I must remain calm. I'm on deadline too here, don't forget. Oh, the pregnant agitation. Someone is tickling my heart with delicate fingers. Death is much on people's minds.
Samson Young is therefore an unreliable narrator because he is left in the position of a reporter of events rather than a creator, and his perception of what is going on around him is partial and incomplete. He allows himself to become pressurised by the deadline he is working against and his own excitement, which influences him even though he tries his best to control himself. What the reader is presented with therefore is an unreliable narrator who may not be deliberately concealing the truth but is impacted by his own position as an observer of events.