Natural products are promising tools for discovery of novel pharmaceutical and Agricultural compounds. Emergence of antibiotic resistant microbial strains and the great demand for new and safer antibiotic and antitumor drugs creates a new area to search unique products from natural resources. Actinobacteria are known for their extraordinary ability to produce novel compounds of clinical and pharmaceutical importance. Due to the high rediscovery rate of known compounds from common Actinobacteria, a renewed interest in the development of new antimicrobial agents from rare Actinobacteria especially those inhabiting arid conditions is urgently required to fight the increasing number of multidrug-resistant human pathogens. To facilitate that discovery, this book focuses on the diversity, abundance and methodological approaches targeting harsh habitats-associated actinobacteria and Exploring different bioactive compounds from those microorganisms is the main target.