Milestones in human microbiota research. While many have dedicated their lives to discovering new frontiers far, far away, research is just starting to acknowledge that one of the most sophisticated civilisations ever discovered has been living within every one of us. Alessio Fasano and Susie Flaherty explore how research on the microbiome could bring the dawn of a new scientific revolution, as these microbial hitchhikers may hold the keys to human health. Here, they argue that we need to understand, respect, and engage with them for the benefit of our well-being. "Today, even with our still limited knowledge of our little tenants, we are at the dawn of a scientific revolution — one that, we believe, will lead to a paradigm shift in science and medicine, opening up new ways to treat and prevent diseases as we have never been able to do before. In revisiting the lifestyle trajectory and groundbreaking research that brought us to where we are, it becomes easier to imagine where we might be in just a few years' time."