Paul Joseph Fronczak is an American author, military veteran, and former actor. Born Jack Rosenthal in New Jersey, he is believed to have been abandoned by his parents in July of 1965 and was subsequently mistaken for a kidnapped infant from Chicago named Paul Fronczak. He was raised by Fronczak's parents as their own child. In adulthood, a DNA test revealed that he is not the Fronczaks' biological son. He has written two books about his investigation to find the real Paul Fronczak, as well as his missing twin sister, Jill Rosenthal.