In the late 1970s, Professor Carl Woese proposed, on the basis of ribosomal RNA afﬁliations (gene mapping), that life be divided into three domains instead of two, namely; Eukaryota, Eubacteria, and Archaebac-teria (Woese, 1993). He later decided that the term Archaebacteria was a misnomer, and shortened it to Archaea and Eubacteria to Bacteria. Since the 1970s, DNA base-pair studies (aka genomic stu-dies or gene sequencing) have shown that Archaea are as different from Bacteria as from Homo sapiens. This new approach to taxonomy is still working its way through the scientiﬁc community and some books and articles still ocassionally refer to archaea as types of bacteria. Prior to genomic studies, and based on their morphology and staining response, the archaeal Halobacteriaceae were grouped with the bacterial Gram-negative rods (a gram positive or gram negative description indicates whether or not the bacterial cell wall reacts with Gram’s stain).