Field emission is one of the most promising areas of vacuum nano- and microelectronics. This chapter reviews current achievements and problems in studying carbon-based field emitters. It is a detailed elaboration of topics partly addressed in the authors’ textbook “Field Emission Electronics”. The review is multipartite. The first part gives general information about carbon-based materials, describing their structures, manufacturing methods for field emission cathodes, and basic features. The second part considers and analyzes some special modern electron emission theory that applies to field emission from carbon-based materials. This is followed by results on the field emission properties of different forms of carbon-based materials. The last part features applications and technological devices using carbon-based field emission cathodes, including descriptions of devices and their design, and prospects for further development. Here, the authors pay particular attention to their own papers on these topics.