The human body is like an exceedingly well-fortified castle, defended by billions of soldiers - some live for less than a day, others remember battles for decades, but all are essential in protecting us from disease. This hidden army is our immune system, and without it we could not survive the eternal war between our microscopic enemies and ourselves. Immune explores the incredible arsenal that lives within us - how it knows what to attack and what to defend, and how it kills everything from the common cold virus to plague bacteria. We see what happens when the immune system turns on us, and how life is impossible without its protection. We learn how diseases try to evade the immune system and exploit its vulnerabilities, and we discover how scientists are designing new drugs to harness the power of the system to fight disease. Do transplants ever reject their new bodies? What is pus? How can your body make more antibodies than there are stars in our galaxy? Why is cancer so hard for our immune system to fight? Why do flu outbreaks cause a spike in sleep disorders? Can we smell someone else's immune system, and does that help us subconsciously decide who we fall in love with? In this book, Catherine Carver answers all of these compelling questions, and many more besides. Drawing on everything from ancient Egyptian medical texts to cutting-edge medical science, Immune will take you on an adventure packed with weird and wonderful revelations about your own internal defensive system.