Working through a modern detailed textbook on the subject can be a daunting project for any student or professional, and the sheer volume of material presented in such textbooks is often prohibitive. The aim of this book is to explain the key concepts of electric circuits in a simple, to the point manner, while making use of worked examples. It is written in three parts, covering static circuits in the time domain, dynamic circuits, and sinusoidal sources and the so-called AC paradigm, in that order. The book focuses on models of the real world, and discusses the basis as well as the limitations for each one to show how they enable the design of systems. Detailed knowledge of the underlying physics is not required to understand the material. The text emphasizes learning directly on the time domain, so models like Laplace and Fourier transforms are not included. The purpose is to use direct time domain numerical solutions of linear systems of equations and differential equations on modern computers. The solutions are explained and highlighted in the book, with several examples as well as a MATLAB source code. Circuit simulation using software such as SPICE is mentioned, but not explained in depth. As this book deals with electric circuit theory at an introductory level, derivations are kept to a minimum and ideas are communicated through practical applications. It is aimed at newcomers or professionals who want a refresher course, but the author provides several references to more in-depth work if the reader seeks more information.