Since 1984, the GRC on Archaea gathers all scientists that share a passion for these microorganisms to discuss the latest developments in the field from a wide range of disciplines including: microbiology, molecular, cellular and structural biology, biochemistry and biophysics, ecology, genomics and evolution. The spectrum of topics discussed in this conference provides the broadest view on archaeal research, and the ideal platform to exchange scientific discoveries and unite them in pursuit of new lines of investigation. For the 2019 conference, each session seeks to place Archaea in a comparative context by emphasizing features of their biology that are unique, or shared, with Bacteria and Eukaryotes, and their impact on the evolving Tree of Life.