This paper considers the case of a famous and dedicated investigator whose report on Mars seized the imagination of masses of intelligent laymen and resulted in a major scientific controversy. Lowell, who was a distinguished modern astronomer, devoted a great part of his life to the scientific investigation of the various surface features of Mars. Hofling's study is based on Lowell's writings and biographical data. The perception of the canals may be categorized as illusory, and his conviction of their presence contrary to fact is described as an idée fixe. The heavy influence of unconscious forces taking the final form of incompletely sublimated voyeuristic impulses resulting from unresolved Oedipal conflicts are given as the explanatory conclusions by the author.