Just to give a heads up, this is a reprint of a document from 1888. So for everyone looking for information Yersinia pestis or how it was carried by fleas you will be disappointed. That was discovered later. Also this was when the miasma theory was falling out and germ theory replaced it. So there does appear to be a bit of both sprinkled in. He does talk from time to time about bad air coming from the earth being the cause. With that said however this is still a good book. It's major key points is the detail involved with the patients disease, the overall death toll and how it spread across europe. It also goes into a lot of detail about what happened afterwards. Like how the plague caused the weakening of the catholic church when the fanatics came in and how the Jews were blamed and persecuted for it. The second part of the book talks about the dancing mania which is really just a continuation of the black plague. The dancing mania, which caused hoards of people to dance until they died, starts right after the black death is over in Europe and continues up until the late 1700s. He goes into a lot of description of this and how it was most likely a psychosis from all the mental anguish mixed with superstition.