The goal of this book is to survey the role of zero and nothing across human activities. The previous applied science chapters focused on how analytical chemistry is used for the detection and quantification of substances that could impact human health. This chapter employs many of these same analytical techniques and endpoints but discusses their use in the legal monitoring of chemicals and drugs used in illicit activities. Here simple detection is the endpoint. Topics include doping in human sports such as the Olympics and horse racing, as well as detecting drugs of abuse. The difference between alcohol screening for impairment of an adult’s driving versus the detection of alcohol use in minors is discussed. The chapter briefly introduces the use of zero in diverse endeavors ranging from finance, end of life issues, and climate change. As discussed throughout the text, the unique number zero has the tendency to focus attention upon itself in a manner that is very different than other numbers. It can be a transition or threshold between something and nothing, an effect and no effect, bankruptcy and solvency, or life and death.