Researches, Chemical and Philosophical; Chiefly Concerning Nitrous Oxide, or Dephlogisticated Nitrous Air, and its Respiration is a seminal scientific work authored by the renowned chemist Humphry Davy, first published in 1800. This groundbreaking book documents Davy’s extensive experimental investigations into the properties, preparation, and physiological effects of nitrous oxide—commonly known as laughing gas. Through a series of meticulously detailed experiments, Davy explores the chemical composition and reactions of nitrous oxide, its synthesis, and its behavior under various conditions. The book is notable for its vivid descriptions of self-experimentation, as Davy and his colleagues personally inhaled the gas to observe its effects, recording sensations of euphoria, altered consciousness, and pain relief. These observations laid the foundation for the later use of nitrous oxide as an anesthetic in medicine. Davy’s work is not limited to nitrous oxide alone; it also delves into broader chemical and philosophical questions of the era, including the nature of gases, the process of respiration, and the theoretical framework of phlogiston versus the emerging understanding of chemical elements and compounds. The book is structured as a series of essays, experimental reports, and reflective commentaries, providing insight into the scientific methods and intellectual climate of the late 18th and early 19th centuries. Rich with empirical data, personal anecdotes, and theoretical speculation, Researches, Chemical and Philosophical stands as a landmark in the history of chemistry and physiology, showcasing Davy’s innovative spirit and his pivotal role in advancing scientific knowledge.