The idea of nothing, as well as its assignment to the specific number zero, is encountered in many fields ranging from mathematics to philosophy, the pure sciences of physics and chemistry to its practical application in disciplines including toxicology, food safety, statistics, advertising and the law. Constantly we are exposed to zero in areas far beyond mathematics where we are tempted by zero calorie soda to credit cards with 0% interest. Other counting numbers do not share this unique aura. Seems like such a simple question; what does zero mean? Why would anyone care if people can’t agree on a definition? Zero is a misfit amongst the normal so-called counting numbers. It defies definition as it reflects nothing, emptiness, or a void. This introductory chapter surveys where zero and nothing are encountered across wide ranging swaths of human endeavors from mathematics to thermometers to deep space to scales to geography to food safety and roulette wheels, thereby framing the focus of the rest of this book.