It is a great pleasure to introduce this E-Book of COMPEL with selected extended papers presented originally at the 24th Symposium on Electromagnetic Phenomena in Nonlinear Circuits (EPNC 2016) held from 28th June to 1st July 2016 in Helsinki, Finland. The 24th EPNC Symposium was organized by Aalto University, School of Electrical Engineering (Finland), Polish Academy of Science and Polish Society for Theoretical and Applied Electrical Engineering – Poznan Section. Professor Anouar Belahcen from Aalto University was Chairman of the Organizing Committee.The first Symposium on Electromagnetic Phenomena in Nonlinear Circuits took place in Poznan, Poland, in November of 1972. The first 11 conferences were local meetings, although speakers from other countries also participated. The last 13 conferences were international events with proceedings published in English. Initially selected papers from EPNC conferences were submitted to regular issues of COMPEL. After EPNC 2004 in Poznan, for the first time selected and extended papers from EPNC were published as an E-Book of COMPEL. The current issue of COMPEL is the seventh such E-Book.The aim of the EPNC 2016 was to present the recent advances in the analysis and synthesis of nonlinear electric and magnetic circuits, nonlinear optics and nonlinear electromagnetic problems in medicine, as well as to provide the forum for discussion and dissemination of recent results on applications of nonlinear phenomena in electrical engineering. The EPNC conferences are intended to be an opportunity to exchange ideas and experiences between specialists as well as young PhD students in electromagnetic field modelling, electric drives, electronics, electrical machines, and electric and magnetic materials. Topics of the symposiums included: Ferromagnetics and Magnetic Circuits, Semiconductors and Nonlinear Electric Circuits, Nonlinear Optics and Wave Propagation, Nonlinear Electromagnetic Problems in Medicine.