This book starts at the beginner level. The aim is to provide the reader with a complete understanding of foundations of electricity and radio-electronics. These foundations are slowly built upon and culminate at a solid, advanced level. In this third edition, new material has been added because of an update of the HAREC standard. This book is aimed at radio amateurs in any country as well as electrical and radio technicians. This book aims to provide a clear understanding of radio and electrical concepts. Most of the mathematics is typical of radio technician level. This book exceeds the standard prescribed by European Conference of Postal and Telecommunications (CEPT) TR61/02