Also in the book - the "spanish" flu was called that since Spain was the only place with a free press at the time (e.g., US press was not free at the time) + massing of young men in US in camps - like Ft Devens. Flu traveled from overcrowded camp to camp and then jumped to local populations along rail lines (and then overseas as troops were shipped out) He describes it well, though would make a great visual as it moves from Boston to Chicago to NYC back into Providence/Brockton (which are just south of Boston). Transmission along rail (and shipping) lines.