This book was written before COVID-19 was a thing, and every time the author wondered what "the next Big One" (AKA the next pandemic) would be, I was just like "Well I guess he has the answer now!" Actually, the last chapter actually mentioned that one of the types of viruses that would most likely be involved in the next big pandemic was coronavirus, and well...RIP, I guess.

Overall, this was a fascinating look at the world of viruses, zoonotic spillover (the process of a virus mutating to a point where it jumps from animals into humans), and various viral illnesses that have emerged relatively recently in human history. The author covers how viruses work, discusses the effects of these various viruses/illnesses in people, and follows the research into how and where different illnesses may have spilled over into humanity. It was very detailed and scientific writing, but done in a way that was definitely understandable and decently easy to follow along with. The author has done a ton of legwork for this book, including traveling all over the world, getting involved with fieldwork and talking with experts, and citing various respected sources so that he can speak with an expert's knowledge.

A huge theme in this book is how humans are the engineers of our own destruction. By that, I mean that humanity is destroying natural habitats, ranging into the rainforest or other uncharted territories, and engaging in inhumane farming practices (overcrowding, animals standing in their own waste), all of which leads to encounters with new viruses, chances for multiple iterations of viral mutations, and inevitable spillover into human populations. It really made me really fucking hate how humanity tramples over everything it doesn't understand and how we as a species have no respect for the natural world or the other creatures living in it. People constantly forget that we are part of ✨the circle of life✨ and that what we put into the world will come back to us ten-fold. (See, this is why I prefer animals a hundred times over humans.)

Another thing that came up in this book is how the behavior of humans will largely dictate how much we are affected by the next big pandemic, and based on the behaviors of people during COVID...yeah, I don't really have much hope. The idiots who made wearing masks and vaccinations all about "politics" are essentially ignoring the fact that viruses don't give a shit about politics and will kill everyone nonetheless if given the chance. When it comes to things like public health, "personal freedoms" should not be a factor, not when everyone is affected. And now, with how much the current administration has gutted the CDC and scientific research in general, we are absolutely not prepared for the Next Big One, whatever it is. (Have I said fuck AI and fuck Trump yet?)

The jist of the book is this: The next pandemic will inevitably happen because humans are living so densely and traveling all across the globe, giving viruses a chance to mutate and transmit across the globe; at some point, a mutation will be the exact one needed to achieve high transmissibility and lethality, and we don't know when or what it will be. All we can do is be vigilant and hope that when it does happen, the people who are in charge will actually do the right thing and listen to the science.