Preface.- Introduction.- PART 1: ARTIFICIAL LIGHT AND HUMAN TEMPORAL ORGANIZATION.- Artificial light and its physicochemical properties (by Fabio Falchi).- Light and dark cycles as a basis of temporal organization.- The biological clock and its entrainment by photoperiod.- LAN exposure and its potential effects on daily rhythms and seasonal disruptions.- Melatonin (MLT) -"hormone of darkness" and a "jack of all traits".- PART II: LIGHT POLLUTION, ITS KNOWN HEALTH EFFECTS AND IMPACT ON ENERGY CONSERVATION.- Introduction and spread of artificial illumination - a human history retrospective.- Biological definition of light pollution.- Light pollution as a general stressor.- The effects of light pollution on animal rhythms and ecology.- Light pollution and hormone-dependent cancers: summary of accumulated empirical evidence.- PART III: LIGHT POLLUTION AND ITS POTENTIAL LINKS TO BREAST AND PROSTATE CANCERS.- Geographic patterns of breast and prostate cancers (BC&PC) worldwide.- Light pollution and its association with breast and prostate cancers (BC&PC) in population-level studies.- Selected methodological issues of Light-at-Night (LAN) - Breast and Prostate Cancers (BC&PC) research.- Dark-less world - what is next? (Conclusions and prospects for future research).- BIBLIOGRAPHY.- ADDITIONAL READING.