This book provides a comprehensive introduction, basic theory and applications of Impedance Spectroscopy with a focus on its link to dielectric phenomena in material and data interpretation. It provides a step-by-step guide to a methodology that ensures a clearer interpretation of the collected data. It simplifies this technique by summarizing the results published by knowledgeable researchers in the field, while presenting some new cutting edge methods for data acquisition, data analysis and interpretation. Each chapter is followed by sample exercises to help explain the concepts presented. The book is based on a set of notes that have been developed over the last twenty years of teaching a full-semester course at Georgia Tech.