The epilepsies are devastating neurological disorders for which progress developing effective new therapies has slowed over recent decades, primarily due to the complexity of the brain at all scales. This reality has shifted the focus of experimental and clinical practice toward complex systems approaches to overcoming current barriers. Organized by scale from genes to whole brain, the chapters of this book survey the theoretical underpinnings and use of network and dynamical systems approaches to interpreting and modeling experimental and clinical data in epilepsy. The emphasis throughout is on the value of the non-trivial, and often counterintuitive, properties of complex systems, and how to leverage these properties to elaborate mechanisms of epilepsy and develop new therapies. In this essential book, readers will learn key concepts of complex systems theory applied across multiple scales and how each of these scales connects to epilepsy.