I'm not going to go into extreme detail about this book as others have written great reviews in that vain. Briefly this book shows how the "microbiome" has influenced life for billions of years, so much so that the heavy use of antibiotics and attempt at sterilization of our bodies and environment over the last 50-100 years may be hurting as much as helping. Our attempts kill the good microbes as well as the bad. So... the trick is determining what is the right level of sterilization we should shoot for.
This book does warn that much of the scientific work is still in its infancy but there are some promising trends. All in all I think this books makes the argument that we shouldn't look at bacteria as an enemy to wage all out war on, but more as companions both good and bad. Some we can, and have without even knowing it, form partnerships. I for one am glad some people already have this view else I would be able to drink my beer!
I can't recommend this book highly enough. There is no heavy technical or confusing jargon. It is a very easy and informative read with a little humor interspersed throughout.