Microbial fuel cells are very promising as renewable energy sources. In addition to electricity generation, microbial fuel cells can be used for wastewater treatment, desalination and biofuel production. The book addresses characterization techniques and operating conditions of microbial fuel cells, as well as the usefulness of various types of anode and cathode materials. Keywords: Microbial Fuel Cells, Renewable Energy Sources, Biocatalysts, Wastewater Treatment, Desalination, Biofuel Production, Micropower Generation, Microalgae, Carbon Nanotube Anodes, Carbon Nanotube Cathodes, Biofuel Production from Food Waste, Microbial Desalination Cells, Microbial Ethanol Production, Microbial Propanol Production.