At every moment, within your body and all around you, trillions of microscopic combatants are fighting an invisible war. Countless times per second, viruses known as bacteriophages invade and destroy bacteria from within, leaving all other cells, including our own, miraculously unharmed. These "phages" are the most abundant, diverse biological entity on Earth - but also the most underappreciated and misunderstood.The Good Virus tells their strange, remarkable story for the first time, from their discovery by a renegade French Canadian scientist more than a century ago to their emergence in the present day as our unlikely allies in the struggle against antibiotic-resistant infections. We learn how this "phage therapy" was repeatedly shunned by Western medicine but flourished behind the Iron Curtain, and follow scientists now unlocking how phages shape evolution and life on our planet at large. Celebrating the paradoxical power of viruses to heal, not harm, The Good Virus will change how you see nature's most maligned life forms.