We studied the important events in the life and work of Puerto Rican scientist and politician Narciso Rabell Cabrero (1873-1928). He lived in the turmoil of the change of sovereignty from the Spain regime to the United States of America regime during the American-Hispanic War of 1898. Despite this turmoil, he made contributions in the natural history of Puerto Rico, especially in paleontology, archaeology, pharmacy, botany and politics. Rabell Cabrero was a man without boundaries. A genealogical summary is also provided.