Just started "The Bible Unearthed"

[Won2blv]

I just started this book. I know that I am going to have a lot of questions. Anyone here pretty well educated on this topic and willing to field some questions as they come up? One general question, how are archeologists able to make sure (or close to) conclusions based off of centuries old cities? Like these cities that are 2500-3000 years old, sometimes I read about new discoveries based off of a pottery shard or something like that. I saw Pompeii recently and was amazed by its preservation, but this is a major anomaly right? Most cities aren't preserved by layers of volcanic ash. Anyway, thanks for the help