Could someone recommend some good books on the plague epidemics during the middle ages?
"A" book I could suggest is "The Black Death" by Philip Ziegler ISBN 0 86299 838 7. It is "Good" in the sense that it appears to be well researched and has a comprehensive biography including non-English language source material. He also discusses the historical evolution of some of the controversial issues about the social and economic impact of the plague.
Another book you might find interesting is "Plagues and Peoples" (Sorry, don't have it with me not sure of author or ISBN). This one is not about the plague(s) of the mid 1300's specifically, but rather considers the co-evolution of humankind and microbes.
Both of these were published several decades ago, there are undoubtedly more recent treatments.