In the universe of Neil Gaiman's "American Gods", pagan gods exist and walk the Earth in material form. They are called into existence when someone begins worshipping them and their power is proportional to the number of worshippers and the strength of the devotion of those worshippers. They cease to exist only when the world forgets them completely.
America is a nation of immigrants, so it is not surprising that many newcomers brought their gods with them from the old country. However, as those immigrants and their descendants began to assimilate into American society, their belief in the old gods diminished and often disappeared entirely. The old gods were left to wander the continent - immortal yet powerless. In their place, Americans worshipped the new gods of television, industry, and the Internet.
"American Gods" tells the story of Shadow Moon, who became a pawn in the war between the old gods and the new gods. Shadow's wife died just before he was released from prison, so he accepted a job protecting Mr. Wednesday, a former deity now making his way as a con man. As they journey across America, Shadow and Wednesday meet gods, goddesses, mythical creatures, pseudo-government agents, and a walking corpse.
The looming war involves hundreds of gods from dozens of pantheons, each with their own agenda. Like the deities of the ancient world, these gods are full of human weaknesses, such as pride, anger, lust, and pettiness. They fight because they fear that there is not enough faith in the world to sustain them all. They seek a clash of titans to escape their current hand-to-mouth existence.
Gaiman weaves a complex story involving many characters and places and he breathes life into each. He layers his own mythology on top of the legends passed down from ancient Greeks, Scandinavians, Egyptians, Africans, Native Americans, and others. The story may not be true, but it is plausible. Gaiman creates rules for his universe, and he sticks to them.
Some readers will not like the tangential turns that the book sometimes takes - the story of African American slaves invoking their ancestral gods to cope with the horrors of plantation life; the tale of a jinn reduced to driving a taxicab and dreaming of restarting his life; and the tragedy of a child raised alone in darkness until he is sacrificed by his tribe. But these tales add color to the legends of the main story and sometimes they tie in directly with the plot.
"American Gods" is a darkly entertaining story of a con man and an ex-con showcasing the underbelly of America as written by an English immigrant. It is an adventure story and a travelogue and a statement about the fickleness of society.
Even by the standards set by Neil Gaiman's other novels, "American Gods" is a great story!