Your body has approximately 10^13 cells in it. And yet there are approximately 10^14 microbes crawling all over your skin, inside your respiratory tract, gastrointestinal tract and other, um, 'nether regions'. This is a vibrant and very complex ecosystem we carry around on, and in, us. In the gastrointestinal tract alone there may be over 400 different types of microbes!Tannock, professor of microbiology, author also of _Medical Importance of the Normal Microflora_ and _Probiotics: A Critical Review_, gives us here an overview of the remarkable preponderance of the indigenous microbiota. The book straddles the line somewhat between a general readership book and a book for students of microbiology, although it definitely leans toward the latter. For the astute layperson, it contains many fascinating bits of information. Indeed, I would like to see Tannock come out with a longer version aimed squarely at the general science readership.Chapters are as follows:1. More than a smell: the complexity of the normal microflora2. Happy Birthday: the acquisition of the normal microflora3. Sticky Microbes: the association of microbes with host surfaces4. Invisible forces: the influence of the normal microflora on host characteristics5. Undesirable company: the role of the normal microflora in disease6. Internal renewal: the potential for modification of the normal microfloraAt just over 100 pages, it is a quick read, despite some technical text. References at the end of each chapter are to professional journals and textbooks. Perhaps it is because of the book not catering exactly to a particular category of reader that has made it scarce, but whatever the reason, I had a hard time ordering this book through Amazon and ended up getting it via Kluwer Academic Publishers in Norwell, Mass.As in his other books, Tannock conveys the interdependencies of our symbiosis with the microflora, and as he says in this Preface:"Our relationship with the normal microflora provide excellent examples of ecological balances that have evolved between species, and the repercussions that ensue should the balance be tilted in favour of one or another partner. An appreciation of this concept is important for all those who study biological sciences."