Linnaeus (1754) was first time gave the name of algae to a group of plants. Agardh (1864) arranged algae in six well-defined orders: Diatomaceae (including desmids), Nostochineae, Confewoideae, Uluaceae, Florideae and Fucoideae and described 20 genera. Significant works during these years were the work of Kuetzing (1843-1849) who described many species. Hassall (1842-1845) made an outstanding contribution in which he recorded many species.

Octogenarians, such as myself enjoy thinking about those adventures in a long life that continue to energize our memory banks The stories collected in this book are true and illustrate a time when museums were less bureaucratic and more idiosyncratic than most of them are today. But idiosyncrasy was exactly the circumstance of the "Nation's Attic" when I joined that community of scholars and researchers back in the mid twentieth century. These stories recount some marvelously eccentric professional behavior and collections equally eccentric which include wonders such as mermaids, simian astronauts, flesh eating beetles, and a silk purse made from a sow's ear. These people and their exotic behavior were observed daily by a new employee who thought that an institution as famous the Smithsonian would be a citadel of decorum and elegance. Not so and happily not so for my adventures among the museum's colorful inhabitants made the business of collecting history absolutely fascinating. Benjamin Lawless graduated from the University of Illinois as an accomplished portrait painter who discovered early on that his skills in capturing a human likeness were not nearly as useful as those of capturing the history of America through museum exhibitions. His fortunate encounter with one of America's great museums, the Smithsonian Institution, resulted in a lifetime of employment among interesting people and world class collections that entertained the author so much that after his retirement the memory of it resulted in this book. When not writing or sketching exhibition ideas for history and science museums around the country, the author sits in a house that he hammered together on the banks of the Potomac River outside of Washington, D.C. observing eagles, ospreys, beaver, deer and foxes who tend to believe what is mine is also theirs. It is truly a delightful way to spend one's sunset years.

In the recent past, many advances have been made in the field of biology and biotechnology of algae, especially microalgae. This book includes chapters on taxonomy, diversity and physiology of blue-green algae as these organisms are most important from biotechnological point of view. Use of algae as biofertilizer, source of natural colours, bioactive compounds, phytochemicals with pharmaceutical and biotechnological applications, food and feed has been discussed. Environmental pollution is the major problem all over the world. The potential of algae in combating water pollution is also highlighted. Depleting fossil fuel is another concern and it is felt that there is a need for alternative renewable resources. Algae as a potential source of biofuel are also discussed in this book

This volume is written with the objective of covering the basic issues in biological nitrogen fixation such as: the physiology, biochemistry and molecular genetics of nitrogen fixation; and the role of signal molecules and host gene expression in nodulation and nitrogen fixation. The book also details recent developments in biofertilizer technology, such as: the immobilization of cyanobacteria; endophytic nitrogen fixation; and solubilization and mobilization of nutrients by phosphobacteria and VA mycorrhiza and their role as bioinoculants.

"Diversity is the hallmark of living things on earth today. In its absence the earth's surface would be as monotonous as that of the moon or the planets about which we know". The word diversity means variety, diverseness, differences, variations among the individuals. The term Biodiversity refers to the totality of Genus, Species and Ecosystem of the region. It is fact that all the species can be occurring at one place whether or not a species can occur on a site. It is determined by the environmental conditions of the site and the range of tolerance of the species.