The numerical approximation of Maxwell's equations, Computational Electromagnetics (CEM), has emerged as a crucial enabling technology for radio-frequency, microwave and wireless engineering. The three most popular 'full-wave' methods - the Finite Difference Time Domain Method, the Method of Moments, and the Finite Element Method - are introduced in this book by way of one or two-dimensional problems. Commercial or public domain codes implementing these methods are then applied to complex, real-world engineering problems, and a careful analysis of the reliability of the results obtained is performed, along with a discussion of the many pitfalls which can result in inaccurate and misleading solutions. The book will empower readers to become discerning users of CEM software, with an understanding of the underlying methods and confidence in the results obtained. It also introduces readers to the art of code development. This book is aimed at senior undergraduate/graduate students taking CEM courses and practising engineers in the industry.