Today is Free Comic Book Day, and if you can’t make it to your local comic store, there’s one book that you can find online: Germ Warfare: A Very Graphic History, written by Max Brooks, the author of World War Z. The 44-page graphic novel is a free download from the Blue Ribbon Study Panel on Biodefense, and looks at humanity’s history with biological warfare.

The Blue Ribbon Study Panel on Biodefense commissioned the project, which was illustrated by J. Nino Galenzoga and colored by Joel Santiago and Patricia Beja. The group was founded in 2014 to “provide for a comprehensive assessment of the state of U.S. biodefense efforts, and to issue recommendations that will foster change.”

Brooks notes that he wrote the book for the commission because he recognized the dangers that diseases and epidemics pose to the public, especially at a time where many question whether or not vaccines work. (They do.) “Preventing the next plague begins with education, and as taxpayers and voters we need to understand what we’re up against,” he says. “the experts can’t help us if we don’t help ourselves. We need to find an informed middle ground between blind denial and blind panic.”

The comic is a quick read, and is designed to provide a broad look at our relationship with germs and how they’ve been used throughout history for malevolent purposes. Brooks covers the earliest known instances of germ warfare, Scythian archers dipping their arrows into animal dung and Mongolians catapulting dead bodies over city walls, and works his way up to more recent efforts, such as when European colonists deliberately infected Native Americans with smallpox, countries experimented with germ warfare programs during the First and Second World Wars, to when a cult tried to infect an Oregon town in 1984.

Brooks also uses the book to examine the history behind the efforts to treat diseases throughout the ages, through the recognition that measures like doctors washing their hands, keeping drinking water free from waste, and vaccines stopped or slowed the transmission of diseases. He also uses the book to outline the steps that can be used to stymie such efforts, from effective regulations like food inspections, to effective disease monitoring from federal agencies.

The book is an interesting (and pointed) look at the issue, with a key takeaway: the most effective tool for any biowarfare attack is ignorance and public apathy.