Most zombie-related books tend to feel the need to beef the zombies into something more. For example, "Monster Island", where the zombies are linked and controlled by a master zombie - whaaaaaaaat?
Max Brooks' impressive book paints a picture of an alternate history, one where zombies were a reality and something that humans fought against for over a decade. The book is told through a series of 'interviews' with survivors, each giving their own insight into a particular event in the 'zombie war'.
Thankfully, Brooks is skilled enough to make this compelling enough without having to resort to extravagant tangents.