Book excerpt: This book summarizes the various areas of research in metagenomics and their potential applications in medicine, the environment and biotechnology. The book presents the recent advances in theoretical, methodological and applied aspects of metagenomics and highlights their applications in the fields of environmental microbial forensics, bioremediation, drug-discovery and agriculture. In addition, the book discusses various metagenomics approaches used for understanding the microbial physiology and biochemistry. Lastly the book describes a range of bioinformatics tools and computational methods for metagenomics analysis as well as the functional diversity and dynamics of microbial communities colonizing the human skin.