Is it possible that the air we breath affects mood? According to the literature on negative air ions, the answer is yes. In the 1980s biometeorology indicated the action of atmospheric conditions on psychological wellbeing describing “serotonin irritation syndrome” and later “climatic heat stress”. Empirical findings were followed by controversial evidence about the effects of negative air ions in laboratory and clinical settings. This book provides an up-to-date overview of the biomedical literature in this topic. First, empirical and experimental data are discussed. Methodological issues are then considered. Finally, the clinical applications of the negative ion devices are reported. Written by two of the most creative voices of psychology and engineering in the New Millennium, The secret in the air is an inspired, provocative and pragmatic exploration that will challenge and transform your outlook on mood disorders. A must-read for students and researchers in psychology and psychiatry. It will also appeal to psychoterapists and mental health workers.