Newly revised for 2018, the concept of the human microbiome is teaching us a new understanding of what it is to be alive, indeed to be a human being. Up until now your only concept of the microbiome (if you had one) would probably be limited to the bugs inside you that help your digestion. You may have heard of the subject talked about in the press as the importance of maintaining a balance of 'good' and 'bad' bacteria to ensure a healthy colon (large intestine). This is a vastly simplified version of events, primarily divulged to the public to shift 'functional foods' like yoghurt drinks and probiotic-enhanced foodstuffs which aim to restore the gut. This is a fallacy. No one product can do this, other than temporarily. When you begin to understand the nature of the trillions of microbial species that live within and on you, you will understand that they are no less than an ecosystem. My aim for this book is no less than to document a revolution in our understanding of what it means to be human. The full complexity of the microbiome, as it is beginning to be understood, is just such a revolution. This is a very hot topic in science right now with a few scientists beginning to present some of the ideas to the lay public outside of the more rarefied (and seemingly impenetrable) boundaries of scientific discourse (which is primarily conducted through journals and academic books). My aim is to convey the wonder of this information by distilling the best of the current writing on the subject but through the lens of a naturopathic therapist who uses some of this understanding in my practice. I am no longer involved in research myself, although I still use this training to inform my writing, but never losing sight of the essential fact; you have to make the science and art of healing interesting and, crucially, relevant to lay readers. I hope I have managed that- now fully indexed as well as comprehensively referenced.