Focuses on our skin, our armpits, belly buttons.We are not alone. We are home to a trillion cells that are not our own, but are very much the making of us. Both on us and inside us live bacteria, viruses, protozoans, fungi, worms, lice and mites that we carry throughout our lives. To say that we are in a minority in our own body is an understatement. Our ‘private wildlife’ keeps us healthy, sometimes makes us ill and even changes our behavior.