Halobacterium salinarumis a halophilic (salt-loving) archaeon that grows in salt concentrations near or at saturation. Although isolated from salted fish a century ago, it was the 1971 discovery of bacteriorhodopsin, the light-driven proton pump, that raised interest inHbt. salinarumacross a range of disciplines, including biophysics, chemistry, molecular evolution and biotechnology.Hbt. salinarumhave since contributed to numerous discoveries, such as advances in membrane protein structure determination and the first example of a non-eukaryal glycoprotein. Work onHbt. salinarum, one of the species used to define Archaea, has also elucidated molecular workings in the third domain. Finally,Hbt. salinarumpresents creative solutions to the challenges of life in high salt.