This book is an introductory course on quantum theory accessible to anyone who is interested in obtaining an insider's knowledge of the subject, but who may not have studied physics at the college level. No mathematics is required beyond middle school algebra. Exercises are provided throughout the book, with answers at the back. This book can be used for self-study or as a textbook in an undergraduate or high school curriculum. Sample Chapter(s) Preface Chapter 1: Introduction Contents: Introduction Newtonian Physics Statistical Mechanics The Concept of a Field The Ultraviolet Catastrophe Absorption and Emission of Radiation Matter Waves The Special Theory of Relativity The Geometry of Space and Time The Heart of Quantum Theory Angular Momentum and Spin Quantum Theory and Relativity Tunneling: Quantum Magic? The Spatial Wave Function Conclusion Readership: Undergraduate or high-school students and readers interested in quantum theory.