Most of us considered microbes little more than nasty germs before science recently began turning our view of the microbial world on its head. A “microbe” is a bacterium and any other organism too small to see with the naked eye. After decades of trying to sanitize them out of our lives, the human microbiome – the communities of microbes living on and in us – is now all the rage. And yet, some insist that we can’t really call microbes “good.” That’s nonsense.