Consisting of six chapters, written by experts in their field, this book charts the progress made in the use of quantum dots as the signaling component in optical sensors since their discovery in the early 1980s. In particular, it focuses on CdS-, CdSe-, and CdTe-type QDs due to their emission in the visible region of the electromagnetic spectrum. The book begins by detailing the range of methods currently used for the preparation and passivation of core/core–shell quantum dots and follows with a discussion on their electrochemical properties and potential toxicity. The book culminates by focusing on how electron and energy transfer mechanisms can be utilized to generate a range of quantum dot-based probes. This is the first text of its kind dedicated to quantum dot-based sensors and will appeal to those readers who have an interest in working with these versatile nanoparticles.