As we are taking much better account of the unseen majority of life, unravel the biogeochemical processes that microbes facilitate, thereby making planet Earth habitable for all forms of life; as we increasingly identify the rules by which microorganisms interact with co-evolving viruses and macroorganisms in health and disease; and as we find more and better strategies to mitigate the detrimental effects of anthropogenic activities on the abundance, diversity, distribution and activity of microbial communities, Frontiers in Microbiology will be the 21st century approach to communicate all this progress to both the specialist and a wider audience of readers in the field.