The main purpose of this project was to find a possible explanation for the steadily increasing incidence of melanoma in Western countries since the mido20th century.A secondary purpose was to develop models with predictive value in order to estimate future melanoma trends.An initial study showed that Nordic countries and the USA both appeared to have the same exposure-time-specific incidence of melanoma, [1].A second study showed that the incidence of some cancers correlated with variations in melanoma incidence across the Swedish counties, while others (e.g.leukemia) did not [2].Melanoma also appeared to persist at a low and stable incidence in the counties as long as FM transmitters had not yet been substantially introduced.[3].Melanoma incidence appeared to be significantly correlated with the number of main FM towers simultaneously covering an area [1, 4].A model based on a precipitous decrease in the efficiency of the immune defense system (presumably caused by FM broadcasting towers) was able to accurately predict the reported agestandardized incidence and age-specific incidence of melanoma for all birth cohorts during the 20th century [5, 6].