Abstract The aim of this chapter is to prepare the reader to the journey into the direct alcohol fuel cells (DAFCs) learning and deeper understanding. Therefore, a broad overview of the DAFC technology, as well as its definition, is provided. A brief comparison between fuel cells and batteries or combustion engines is made as well as a comparison between the DAFCs and its direct rival—the hydrogen PEMFC. The working principles of the DMFCs and DEFCs are presented together with the description of the two different types of fuel and oxidant supply in active and passive systems. The main advantages and disadvantages of the DAFCs are explained, stressing out the great potential of application in the portable sector. An introduction to the markets and target applications is then offered with the presentation of several examples of products already under commercialization. Finally, the main challenges of this technology are presented.