Human microbiota - the collection of microbes living in and on our body - have a significant impact on human health and well-being. They have been associated with numerous diseases, yet we have barely understood their role in the context of life-style and genetics. Various initiatives are underway around the world to survey the human microbiota at several body sites, characterise them, understand their interactions with the human hosts, elucidate their role in diseases, and design possible therapeutic or dietary interventions.