The protocols in these three books are selected to provide a detailed guide to experiments with the methanogenic, extremely halophilic, and thermophilic sulfur-utilizing Archaea, with overviews to highlight areas of future development. The individual protocols consist of an introduction describing the specific applications of the techniques, step-by-step procedures for applying the protocols, followed by any additional comments that will facilitate successful application of the protocol. A feature of research in this area is the interplay between microbiology, bioengineering, biochemistry, and molecular biology, and authors from all of these fields have been selected to provide these three concise and comprehensive resources for scientists interested in conducting research on the Archaea.