How does the book and the television differ? How does it remain the same?

The television show American Gods is an adaptation of Gaiman’s 2001 novel. Since the work is so lengthy (588 pages in the paperback version), it would be incredibly difficult to adapt the story in its entirety. Though the television series begins as the novel did with Shadow’s early prison release and wife’s death, and while the journey taken by Shadow and Mr. Wednesday, still seminal to the story line, takes roughly the same trajectory, the serial television format lends the show’s creative team a great deal of freedom. Roles of supporting and even minor characters can now expand, allowing them to have interesting adventures and growth arcs of their own. Even if these do not follow events in the novel to the letter, the television series format allows for this type of expansion. It also helps to generate audience interest in the series from members of different demographic groups.
The novel also contains lengthy narrative sequences that would not translate well as pure dialogue: entries from Mr. Ibis’ journal, Shadow’s dreams, and flashbacks, for example. Because television, like film, is a visual medium, a well-constructed tableau or sequence of camera shots can communicate the intent of such scenes quickly and far more effectively.
Other notable differences are how Technical Boy’s character has transformed from overweight geek to sleek millennial, and how the show deals with themes related to hotbed topics, such as immigration.