Salt is an essential requirement of life. Already from ancient times (e. g. , see the books of the Bible) its importance in human life has been known. For example, salt symbolizes destruction (as in Sodom and Gomorra), but on the other hand it has been an ingredient of every sacrifice during the Holy Temple periods. Microbial life in concentrated salt solutions has fascinated scientists since its discovery. Recently there have been several international meetings and books devoted entirely to halophiles. This book includes the proceedings of the "Halophiles 2004" conference held in Ljubljana, Slovenia, in September 2004 (www. u- lj. si/~bfbhaloph/index. html). This meeting was attended by 120 participants from 25 countries. The editors have selected presentations given at the meeting for this volume, and have also invited a number of contributions from experts who had not been present in Ljubljana. This book complements "Halophilic Microorganisms", edited by A. Ventosa and published by Springer-Verlag (2004), "Halophilic Microorganism and their Environments" by A. Oren (2002), published by Kluwer Academic Publishers as volume 5 of "Cellular Origins, Life in Extreme Habitats and Astrobiology" (COLE), and "Microbiology and Biogeochemistry of Hypersaline Environments" edited by A. Oren, and published by CRC Press, Boca Raton (1999). Salt-loving (halophilic) microorganisms grow in salt solutions above seawater salinity (~3. 5% salt) up to saturation ranges (i. e. , around 35% salt). High concentrations of salt occur in natural environments (e. g.
