The blurb for this series says...
"The `Zombie Chronicles' universe, where the zombies don't stay mindless, shambling adversaries. Instead they grow smarter, faster and stronger as they feed on the flesh of the living."
...and to that statement I would add, "And where zombie-fighting humans begin to suspect that they, too, are changing as they struggle to survive in this bleak world."
Author Mark Clodi distinguished The Zombie Chronicles by coming up with the very novel idea that Romero-type zombies could learn and grow as they feed. The human survivors in the Zombie Chronicles world therefore have to content with both types of zombies as they try to survive.
The first three Zombie Chronicles books center upon Max, his best friend Bill, a cop Jane Steward, and a great supporting cast of minor characters -- both human and zombie. Interesting questions are raised: Can a thinking zombie still care about humanity? Could zombie and human work together to overcome the common evil? What qualifies as humanity? There are some grammatical mistakes in the series, particularly in the first book, but for me those faded in significance as I was caught up in the unique "smart zombies" premise, the multidimensional characters (it was particularly interesting to see the world through the eyes of the smart zombies), and the action as Max and friends try to stay alive.
In book two, Discovery, Max flees Denver and heads to the Midwest to find his friend Bill, and see what they can do about the zombies threatening Iowa.