50 years after the death of George Nicholas Papanicolaou (1883-1962): evaluation of his scientific work.

The purpose of this review article is to summarise the scientific work of George Nicholas Papanicolaou, one of the most eminent figures in the 20th century history of clinical cytology and medicine. Fifty years after his death, his work still remains invaluable, from the early steps in biology and zoology to the application of the Pap test as the most important advancement in the prevention of cervical cancer. The publication of his Atlas was the first important step for the foundation of a new branch in medicine, that of exfoliative cytology. His contribution to cytology undoubtedly earned him the title of the "father of exfoliative cytology" and saved the lives of many women worldwide.