I'm new to Neil Gaiman, having only read "Good Omens" before, about four years ago. With "American Gods" I might become inspired to truly dive into this author's rich body of work. This book has a very creative treatise. Old pagan gods still live on as destitute characters in the real world, as long as a few isolated pockets of people still venerate them. Meanwhile, really old gods that are completely forgotten by humanity have disappeared into oblivion. The major religions couldn't even obliterate these decrepit old pagan gods for good, but the real gods of modern America may finally do it - the harsh gods of money and technology. The straight man in the novel is a hapless ex-con named Shadow, who eventually realizes that the bizarre characters he keeps running into are those decaying pagan gods who need his help in their struggle. Shadow also eventually bumbles into the realization that these gods are allying themselves with him for a greater purpose. The concepts behind this book are indeed fascinating and highly creative. Unfortunately the book must be docked one star because the action peters out towards the end, and the anti-climax takes way too long wrapping up a bunch of boring subplots. But still, Neil Gaiman is clearly one of the modern masters of innovative, speculative fiction. 

Question: What is the concept of the book?
Answer: concepts behind this book are indeed fascinating