For approximately 4.5 billion years, the Earth has been evolving from a barren volcanic landscape into the vibrant globe full of life that it is today. The transformation of the microbiological experience during last 25 years has alter the microbiologists view of microorganisms. The total no. of prokaryotic cells on earth has been estimated at 4-6 x 1030 (Whitman et al., 1998) and having 106 – 108 separate genespecies (Amman et al., 1995). But more than 99% of bacteria in the environment can not be grown neadily in pure culture which forced the microbiologists to question their belief that the microbial world had been conquered. (Cowan et al., 2000). In this ensuring years microbiologists dedicated intense effort to describing the phylogenetic diversity of environments – Ocean surface, soil etc. The next challenge was to elucidate the functions of these new phylotypes and determine whether they represent the new species, genera or phyla of prokaryotc life. This challenge produces various techniques including metagenomics, the genomic analysis of environmental sample/organisms. Metagenomics has provided to access for more microbial diversity than has been viewed in the petridish. 1365574649.php