This book presents a comprehensive overview of DNA barcoding and molecular phylogeny, along with a number of case studies. It discusses a number of areas where DNA barcoding can be applied, such as clinical microbiology, especially in relation to infection management; DNA database management; and plant -animal interactions, and also presents valuable information on the DNA barcoding and molecular phylogeny of microbes, algae, elasmobranchs, fishes, birds and ruminant mammals. Furthermore it features unique case studies describing DNA barcoding of reptiles dwelling in Saudi Arabian deserts, genetic variation studies in both wild and hatchery populations of Anabas testudineus, DNA barcoding and molecular phylogeny of Ichthyoplankton and juvenile fishes of Kuantan River in Malaysia, and barcoding and molecular phylogenetic analysis of indigenous bacteria from fishes dwelling in a tropical tidal river. Moreover, since prompt identification and management of invasive species is vital to prevent economic and ecological loss, the book includes a chapter on DNA barcoding of invasive species. Given its scope, this book will appeal not only to researchers, teachers and students around the globe, but also to general readers.