Book excerpt: Research on microbes plays an essential role in the improvement of biotechnological and biomedical areas. It has turned into a subject of expanding significance as new organisms and their related biomolecules are being characterized for several applications in health and agriculture. Microbial biomolecules confer the ability of microbes to cope with a range of adverse conditions. However, these biomolecules have several advantages over the plant origin, which makes them a suitable target in drug discovery and development. The reasons could be that microbial sources can be genetically engineered to enhance the production of desired natural production by large-scale fermentation. The interaction between microbes and their biotic and abiotic environment is fundamental to numerous processes taking place in the biosphere. The natural environments and hosts of these microorganisms are extremely diverse being reflected by the fact that microbes are widespread and occur in nearly every biological community on Earth. This metabolic versatility makes microbes interesting objects for a range of economically important biotechnological applications. Most of the biotechniques are established but inefficient genetic engineering strategies are still a bottleneck for selected microbe producing industrial scale biomolecules. Therefore, untapped microbial biodiversity and related metablomics, give a noteworthy wellspring of biologicals for the advancement of meds, immunizations, enhanced plants and for other natural applications. The present eBook volume contains articles on microbial secondary metabolites, microbial biosynthetic potential including biosynthetic gene expression, and metagenomics obtained from microorganism isolated unique from habitats like marine sources, endophytes, thermal springs, deserts, etc.