Applied Synthetic Biology is a fast emerging field of life sciences that brings together engineers and biologists with the aim of design and construction of novel biological systems, gene networks and biosynthetic pathways with unprecedented properties and functions for benefit of human civilization. There are no sharp lines of division between systems biology and synthetic biology. Systems biology is an interdisciplinary field of biological science that focuses on study of complex gene network interactions within biological systems. It can be used in quantitative description of cells or cell processes to refine the computational model or theory. Synthetic biology is a recently expanding area of biological sciences that is useful in the design and construction of novel synthetic gene network with predictive function that can help to change the cell physiology. Systems and synthetic biologists together are conducting research to uncover fundamental principles of biological mechanisms for applications in environmental and health management. The present volume 4 of 12 volume series on Recent Developments in Biotechnology promotes the systems and synthetic biology research for better understanding of cellular mechanism and construction of synthetic gene regulatory networks with the intention to pave the way for next-generation gene therapy and cellular reprogramming. This volume includes discussion on the following topics: o An introduction of synthetic biology o Principles of systems and synthetic biology o Introduction to complex biological networks o Genetic regulatory networks o Genome scale metabolic models in systems biology o Recent developments in synthetic biology o System biology of ageing process o Systematic reduction of microbial genomes o Mathematical modeling of biological networks o Modeling and analysis of biological networks o Liquid-crystalline approach in structural DNA nanotechnology o Application of synthetic molecules in biosensors o Use of micro fluidic devices in synthetic biology o Synthetic gene network engineering for cellular oscillations o Biological computing by the cellular gene network engineering o Directed evolution for advancing synthetic biology o Biotechnology and bioethics The volume 4 contains 17 chapters from 34 researchers and/or academicians representing 8 nations, namely, Brazil, Chile, France, Hungry, India, Italy, Russia, United Kingdom and United States of America giving an overview of the various research activities being carried out in different parts of the world in the field of Applied Synthetic Biology.