Max Brook's World War Z is a bunch of notes that could be turned into a nice novel.
To be fair, I don't recall whether the audiobook version I check out of the library was unabridged or not but World War Z was only mildly interesting at best. Pop culture's current fascination with the undead has eluded me and that's one reason why I gave these 5 CDs a chance in the first place.
I had never given much thought to where zombies might come from and this book provided an answer. The "oral history" format of this tale of the Zombie War was the first audiobook I have listened to that was produced using a full cast (notable: Alan Alda, Carl and Rob Reiner, Mark Hamill). Again, only mildly interesting.