The book "E Cell System: Basic Concepts and Applications" provides a comprehensive introduction to the E Cell System software, which is designed for modeling and simulating biological processes. It is aimed at professionals and students in the fields of molecular biology and systems biology who wish to gain a deeper understanding of the mechanisms and behaviors of biological systems. The book covers the fundamental concepts of modeling and simulation and offers practical guidance on using the software. It is particularly valuable for those looking to conduct qualitative and quantitative analyses of genetic and biochemical networks. The authors, Satya Nanda Vel Arjunan and Masaru Tomita, convey the necessary knowledge in clear and precise language to effectively utilize the E Cell System platform and create their own virtual biological systems.