What makes tears of joy different from tears of sadness? Why is a gut feeling so much smarter than you think? And why is 90% of you not even human? This book turns your knowledge of the human body on its head. The effervescent van Tulleken twins bring their knowledge and charm to the page to reveal just how well our bodies keep secrets from the things that want to exploit it: bacteria, viruses, fungi, parasites, larger predators and, crucially, other people. They reveal the remarkable stories behind the science we are not meant to know, on matters of life and death.

Leading us through these revelations are tales of everyday miracles - the human stories that bind every one of us together through the universal stages of life. Chris and Xand van Tulleken reveal the incredible abilities every human shares, leading us to discover the secrets that make every ordinary human body ... extraordinary.