Through systematic mathematical analysis of biological networks, this course derives design principles that are cornerstones for the understanding of complex natural biological systems and the engineering of synthetic biological systems. Course material includes: transcriptional networks, autoregulation, feed-forward loops, global network structure, protein networks, robustness, kinetic proofreading and optimality. After completion of the course, students should be able to use quantitative reasoning to analyze biological systems and construct mathematical models to describe biological systems.