The book takes place through history, ranging from 1665 all the way to the 1980s. The places the story takes place in are London, Cuba, New York City, the entire world during World War One, in a village in Zaire, and the final chapter is throughout the USA.

The book is about sciententist who are trying to find the cause, and cure of certain illnesses around the world. Some of the methods we still use today.

One of the most important people in the book, was John Snow. He was the first scientist to investigate the cholera outbreak in London in 1854. He was important because he used a method of gathering information about people in the area to figure out where the infection started, by going door to door asking people himself. We still use this method today when we need information about the routine of an individual patient is.

The most important event in this book was probably when the Spanish Flu reached the German lines in WWI. The Germans were planing a massive counter-offensive for the summer, luckily for us, the flu managed to cross over to the enemy lines and made them push back the date of the attack, giving the Allies time to prepare. Had the Illness not been given to the Germans, it is undoubtable that the German's plan would have worked and it might have changed the course of history. They had the manpower to decimate the Allies.

I learned many things from this book, for one, that many doctors thought that "bad air" caused disease and using fragrance could ward off the disease. Another thing is that many people thought that a mosquito could not spread Yellow Fever, it was too small to make any impact, despite the fact that today it is known to be the universal transmitter of the disease. I also thought that it was interesting that "Typhoid Mary" was a healthy carrier of the disease, meaning she showed no sign of being sick, but she was still very contagious, I did not know that humans could be a healthy carrier of any disease. I learned that the Spanish Flu wasn't actually from Spain, but from American army camps, we call it Spanish Flu because newspapers weren't allowed to print things about the war during violent times that would weaken moral of the public, and the troops, Spain was not in the war, so it reported on it freely. Also, Yersinia Pestis actually has three different forms it can manifest in self in, Bubonic, pneumonic, an septicemic plague, all affecting different parts of the body. Finally, London was the first city to have a modern sewer system put in to keep disease from spreading to the drinking water, this was because of the outbreak of Cholera in 1854.

I would rate this book on a scale of one to five as a 4. The book is not for everyone, but I have always wanted to be an epidemiologist, I just wish the book was longer.