This book provides in-depth information about the ecology, diversity and applications of Actinomycetes. The book is divided into two major parts. The first part discusses the diversity, chemical biology and ecology of Actinomycetes. It also covers the discovery of natural products from soil, endophytic and marine-derived Actinomycetes. It includes natural product discovery, chemical biology, new methods for discovering secondary metabolites, structure elucidation and biosynthetic research of natural products. The chapters in this part focus on the effects of biological and chemical elicitation at molecular level on secondary metabolism in Actinomycetes. The second part of the book discusses genomic and synthetic biology approaches in Actinomycetes drug discovery. This part includes chapters focused on the application of metabolic engineering to optimize natural product synthesis and the use of omics data in engineering of regulatory genes. It covers the advanced tools of synthetic biology and metabolic engineering including cluster assembly, CRISPR/Cas9 technologies, and chassis strain development for natural product overproduction in Actinomycetes. It describes the use of bioinformatics tools for reprogramming of biosynthetic pathways through polyketide synthase and non-ribosomal peptide synthetase engineering. These advanced genomic and molecular tools are expected to accelerate the discovery and development of new natural products from Actinomycetes with medicinal and other industrial applications. The book is useful to researchers and students in the field of microbiology, pharmaceutical sciences and drug discovery.