Naïve Bayes Network

The chapter explains that Naïve Bayes can only be used for purposes of classification. Why is this so? Also, is Naïve Bayes a supervised or unsupervised method? If there is an important variable that is continuous, would it still be possible to include the variable in a Naïve Bayes model? If so, what would you need to do to accomplish this? Do a bit of extra research and tell us, what is the difference between Naïve Bayes and a Bayesian Network?