The focus of this book was primarily upon the effects of the Black Death (as you might guess from the title).
Cantor did talk about possible causes of the Plague mostly in the beginning and end of the book. The current theory seems to be the Y. Pestis
carried by black rats with a simultaneous outbreak of Anthrax contracted from sick cattle. Apparently black rats are very slow moving and generally have a very limited range of travel so while it is quite possible they carried the fleas that spread the Plague onto ships which then spread the Plague in various ports, some scientists think it is unlikely that fleas alone could account for the rapid spread of the disease over such a large geographic area.
There is also some discussion of more radical theories about the origin of the Plague, including one theory that this disease, like most diseases, is from outer space and arrives in comet debris.
There is also much discussion about how contemporaries viewed the Plague and tried to treat it. Many Western Europeans viewed it as a punishment from God for sins of the wicked, although the widespread nature of the disease made that explanation somewhat problematic. Muslims believed that it was more of a blessing from God and they believed that dying from Plague made a person as great a martyr and was as honorable a death as dying in battle.
There was also much discussion of Galen and his theories about the four humors and how their imbalances would cause the disease.
The Church viewed human dissection as a great sin, so while there were many advances in other areas, particularly theology and philosophy, there was little advancement in science at that time. There are conflicting views on whether the Plague caused people to become more religious or if it caused people to lose faith in the Church, as the Church was obviously powerless in the face of the Plague.
Not surprisingly, outsiders and Jews were blamed for the spread of the disease. One Jew was "lightly tortured" at least twice before "confessing" that he had poisoned wells which caused the Plague. Jews were driven out of some areas but were often rounded up and burned alive.
The Plague had a great affect on the politics of the time. I must admit, reading this book made me ashamed of my limited knowledge of European History. I have a hard time keeping all the Richards, Edwards and Henrys straight.
The Plague had a profound affect on the lesser nobility, serfs, and yeomen as well. There was much discussion about the fact that the Plague caused a severe labor shortage which hastened the end of serfdom. Serfs were able to demand better wages and standards of living and if they couldn't get it from their current employer they'd move and find work elsewhere. Some governments, including England's, passed laws to try and keep wages at pre-Plague levels. This led to revolts by the peasantry. (Surprise).
The Plague had a profound affect upon real estate law. In fact, much of real estate law in modern America is based upon cases that rose up immediately after the Plague. One of the effects of lawsuits was to free serfs (one could only sue or be sued if one was free i.e. not a serf and the courts were pretty lax about determining a person's status and once they'd been part of a lawsuit they were free even if they weren't before).
Because widowers were entitled to a large amount of an estate, and because the disease seems to have affected more men than women and sometimes the only family member left alive was a woman who would then inherit everything, there was some discussion that the Plague actually helped women gain more independence than they'd had before.
There was also some suggestion that Germany in particular may have been devastated by the Plague, possibly depressing the population so much that it led to some of the troubles of World War I and II. (Other theories say Germany did not lose much more than other locations that were devastated by Plague and the population would have rebounded long before World War I).
It was a fascinating book. Although there were sections that were repetitive and a few small sections that seemed pretty random, the book seemed well researched. Cantor was careful to say what the prevailing theory was but also describe some previous theories and explain why those theories were no longer believed. After reading this book I had a much greater appreciation for the role disease played in European history.