The book is the sequel to David Moody's excellent, deliberately slow-paced Autumn novel which set the stage for his trilogy.
Moody has us follow the patch of several groups of survivors in modern-day England after the outbreak of a terrifyingly fast virus that killed billions of people in seconds, without anybody knowing its origin or its purpose. The group of "countryside" survivors that we got to know in Autumn is featured in this sequel again. It gets back to the City it originally fled from and gets to merge with another group of survivors that got trapped in a university somewhere in the City -hence the book's name.
Moody is keeps delivering a number of messages to the reader in his book, just as he did in the first, and will be doing in the third (Autumn, Purification).
First, the countryside is no ideal place to hide and enhance the chances of survival when faced with a mutating enemy that relies primarily on sound detection, and gets increasingly "articulated". Out there in the open, while silence may be soothing, it may also become the deadliest betrayer too as any sound will act as magnet to those stench-generating masses.
Second, the Army is shown in its full "splendor", ie a mixture of immature conditioning in the face of unplanned threats, and power -when used and organized to take benefit of its very conditioning. Unlike in many other zombie books, the army is not depicted as a "yet-another-enemy-from-within" party. It features good as well as hopeless guys too, just like in the outside. The survivors get to benefit from the army without giving them anything in return, as we would have anticipated normally.
Third, the most intellectually "enlightened" characters of the bunch have no clue about what's happened to the world. Reciprocally, the army's might is barely sufficient to inflict any kind of substantial damage to their "total enemy", the rotting crowd. In other words, neither sheer intelligence nor brute force is a real asset in ensuring self-preservation. What we see clearly in Moody's depiction is the intrinsic value of constant adaptation. Those who can't adapt, don't make it alive.
Pretty good messages I thought. Sounds good to you too? Then read on.
Another finesse of Moody's work is the way the sick bodies evolve. In the first book, they were dumb, inarticulated, helpless, but moving towards the end to the beginning of a rational thought process translating into coordinated actions (banging on the walls, moving to a specific location. Aggressiveness was also starting to show.
In Autumn, the City, aggressiveness becomes the driving factor behind the rotten crowd's actions, making it each day more dangerous and difficult for the survivors to stay alive. This adds another, very effective layer of anxiousness, as the survivors cave in in makeshift shelters for extended periods of times without necessarily being aware of the extent of the dead bodies' mutation outside. That makes for interesting encounters when they finally all meet together again.
But still, the author still has not used the name "Zombie" a single time in this second book, making the pathetic living-deads not so evil after all. And we still don't know what caused this mayhem in the first place, will we ever find out? People we get attached too just die of stupid death (car accidents etc.), so who's going to be the next one? Also, what the hell are the living-deads doing when they get onto living survivors? Do they eat them? Do they just kill them as the result of hate, jealousy, something else? Will we, here again, know at all in the end? All of these very effective narrative and plot techniques are very good at keeping the reader glued to the book, wishing for the end (of the book!) not to come too fast.