Wetlands are ecologically as well as economically important systems due to their high productivity, their nutrient (re)cycling capacities, and their prominent contribution to global greenhouse gas emissions. Around the globe, wetlands are under high pressure due to anthropogenic activities as well as climate change. This volume contributes to the widespread information on the microbiology of wetlands and discusses the gaps therein to be assessed in future wetland research. The key developments in wetland microbiology in the twenty-first century are also explored.