Foreword, Richard Castenholz. Preface, Joseph Seckbach. Introduction to the algal world, Meltem Conk-Dalay. Acknowledgement, Joseph Seckbach. List of Authors and addresses.PART 1: General IntroductionOxygenic photosynthetic microorganisms in extreme environments: possibilities and limitation, Joseph Seckbach and Aharon Oren.PART 2: Phototrophs at high and low lightEffects of ultraviolet radiation on cyanobacteria and their protective mechanisms, Bagmi Pattanaik, Rhena Schumann and Ulf Karsten. The hidden life of algae underground, Werner Reisser. Meromictic lakes as habitats for protists: life in the chemocline and below?, Dag Kaveness and Finn Lovhoiden. Marine phototrophs in the twilight zone, Noga Stambler and Zvy Dubinsky.PART 3: Phototrophs in the marine environmentBiology of the chlorophyll D-containing cyanobacterium Acaryochloris marina, Michael Kuhl, Min Chen and A.W.D. Larkum. Phylogenetics, molecular biology and ecological impacts of a group of highly unusual protists: the dinoflagellates, Shauna Murray. Diatoms: Living in a contructal environment, Frithjof Sterrenburg, Richard Gordon, Mary Ann Tiffany and Stephen Nagy. The margin of the sea: survival at the top of the tides, David Garbary. Seaweeds on the abrasion platforms of the intertidal zone of eastern Mediterranean shores, Rachel Einav and Alvaro Israel. Status of mangrove ecosystem: exploring the potential role of cyanobacteria in restoration and afforestation, M. Sundaraman, T. Boopathi and S. Gopinath. Intertidal sandy flats as a habitat where plastid acquisition processes are ongoing, Noriko Okomota and Isao Inouye. Hydrochemical key to the genesis of calcareous non-laminated and laminated cyanobacterial microbialites, Stephan Kempe and Josef Kazamierczak. Soil and freshwater micro-algae as a food source for invertebrates in extreme environments, Alena LukeA!ova and Jan Frouz.PART 4: Phototrophs in cold environmentsCold tolerance in cyanobacteria and life in the cryosphere, Warwick Vincent. Cyanobacteria in Antarctic lake environments: a mini-review, Shiv M. Singh and Josef Elster. Green cryosestic algae, Jiri Komarek and Linda Nedbalova. Psychrophilic diatoms: mechanisms for survival in freeze-thaw cycles, Thomas Mock and Karen Junge. Algae at extreme low temperatures: the cryobank, Erica Bensen, Keith harding and John Day.PART 5: Phototrophs in hot alkaline and acidic environments and non-thermal acidic habitatsCyanidiophyceae: looking back - looking forward, Gabriele Pinto. Diversity of the cosmopolitan thermophile mastigocladus laminosus at global, regional and local scales, Scott Miller. The thermophilic cyanobacteria of the zerka ma'in thermal springs in Jordan, Danny Ionescu, Aharon Oren, Muna Hindiyeh and Hanan Malkawi. Iron-tolerant cyanobacteria: implications for astrobiology, Igor Brown, Carlton Allen, Daniel Mummey, Svetlana Sarkisova and David McKay. Extreme acidophiles: freshwater algae associated with acid mine drainage, Phil Novis and Jon Harding . Eukaryotic community structure from Rio Tinto (SW, Spain), a highly acidic river, Angeles Aguilera, Linda Amaral-Zettler, Virginia Souza-Egipsy, Erik Zettler and Ricardo Amils. Species composition of Cyanidiales assemblages in pisciarelli (Campi Flegrei, Italy), and description of Galdieria phlegrea sp. nov., Gabriele Pinto, Claudia Ciniglia, Carmela Cascone and Antonio Pollio. A genomics approach to understanding the biology of thermo-acidophilic red algae, Andreas Weber, Guillaume Barbier, Roshan Shrestha, Robin Horst, Ayumi Minoda and Christine Oesterhelt. Enigmatic archaeal and eukaryotic life at hydrothermal vents and in marine subsurface sediments, Andreas Teske. PART 6: Phototrophs under water stress: dry and hypersaline environmentsNorth American desert microbiotic soil crust communities: diversity despite challenge, Valerie Flechtner. Chroococcidiopsis from desert to Mars, Maria Grilli Caiola and Daniela Billi. Chlorophyta on land: independent lineages of green eukaryotes from arid lands, Louise Lewis. Aeroterrestrial algae growing on man-made surfaces: what are the secrets of their ecological success?, Ulf Karsten, Rhena Schumann and Anika Mostaert. The systematics of subaerial algae, Juan Lopez-Bautista, Fabio Rindi and Dale Casamatta. Diversity, distribution and ecology of green algae and cyanobacteria in urban habitats, Fabio Rindi. Diversity of organic osmotic compounds and osmotic adaptation in cyanobacteria and algae, Aharon Oren.PART 7: Adaptation of algae to changing environmentsCyanobacteria: diversity and versatility, clues to life in extreme environments, Lucas Stal. Life in a hypervariable environment: algae of the great salt plains of Oklahoma, U.S.A., William Henley, Jana Kviderova, Andrea Kirkwood, Jessica Milner and Andrew Potter.PART 8: Other microorganisms and extreme habitatsThe fate of biological materials in acidic environments of the Rio Tinto, southwestern Spain, David Fernadez-Remolar, Cesar Menor Salvan, Marta Ruiz Bermejo and Andrew Knoll. Deep-sea microbial eukaryotes in anoxic, microoxic, and sulfidic environments, Virginia Edgcomb, John Bernhard and Sunok Jeon. Fungal associations at the cold edge of life, Silvano Onofri, Laura Zucconi, Laura Selbmann, G. Sybren de Hoog, Asuncion de Los Rios, Serena Ruisi and Martin Grube. The early earth's record of supposed extremophilic bacteria and cyanobacteria, at 3.9 to 2.5 Ga, Wladyslaw Altermann.PART 9: Outlook - SummaryAlgae and Cyanobacteria under environmental extremes: final comments, Joseph Seckbach, David Chapman, David Garbary, Aharon Oren and Werner Reisser.