Over the last decade, the advent of new methodologies has encouraged and extended applications for DNA cloning. DNA manipulation has become simple due to powerful tools that demonstrate exponential growth in applications and the complexity of recombinant DNA technology. The advent of novel cloning techniques has opened the door to more refined applications such as the detection and mapping of epigenetic modifications and the high-performance assembly of combination libraries. The purpose of this book is to discuss the major breakthroughs in cloning techniques and their applications in various areas of biological science that have developed mainly due to the easy construction of novel expression systems.