This book is addressed to researchers and practitioners in the theory and applications of electric circuits. It can also serve as a textbook for Ph.D. students examining applications of modern mathematics to important issues emerging nowadays more and more often in advanced electrical and electronic systems. The book offers effective tools to facilitate the study of all those circuits and systems increasingly penetrating our world, helping to discover their hidden beauty. The material is presented in twelve chapters divided into sections. Usually, first sections are of an introductory nature, explain studied phenomena and announce numerical results. More advanced investigations are presented in subsequent sections. The center of concern is set on existing modern methods as well as continuously emerging new methods of investigations useful for researchers, engineers and practitioners active in many interdisciplinary fields, where physics, electrochemistry, and electric circuits play a key role. Coverage includes: