Archaea is the third domain of life. This group of organisms comprises microbes with unique biochemical and genomic features, some of which resemble those of Eucarya. Their habitats and lifestyles are very diverse, from extremophiles living in harsh environments to soil and marine mesophiles and from free-living microbes to gut-inhabiting methanogens and symbiotes. While it is becoming clear that the archaeal domain may have an independent evolutionary history, its origin and links to Bacteria and Eucarya remain contentious and its placement in the Tree of Life remains a question that demands attention. In this special issue, we invite authors to submit original research and review articles that tackle questions of the origin, diversity, and evolution of the archaeal domain. In particular, we are interested in articles describing both patterns and processes responsible for archaeal diversity at genetic, genomic, biochemical, physiological, and ecological levels.

With this special issue, we honor and celebrate the life and impactful contributions of Carl Woese. His insightful mind is responsible for the discovery of the archaeal domain and for transforming comparative views of microbial diversity into an overarching evolutionary framework. Potential topics include, but are not limited to:

• Genetic, phenotypic, and ecological diversity
• Genomics, metagenomics, and phyloecological analyses
• Adaptation
• Horizontal gene transfers
• Comparative genomics
• Phylogeny of the archaeal domain
• Archaea and the origin of eukaryotes
• Systems biology and archaeal evolution

Before submission authors should carefully read over the journal’s Author Guidelines, which are located at http://www.hindawi.com/journals/archaea/guidelines/. Prospective authors should submit an electronic copy of their complete manuscript through the journal Manuscript Tracking System at http://mts.hindawi.com/submit/journals/archaea/oead/ according to the following timetable: