Jacques Fabrice Vallée (born September 24 1939) is a French‑born computer scientist, astronomer, venture capitalist, and pioneering figure in the scientific study of unidentified flying objects (UFOs) and unidentified anomalous phenomena (UAP). Vallée began his career as an astronomer at the Paris Observatory and later worked at SRI International’s Augmentation Research Center under Douglas Engelbart, contributing to the ARPANET, a precursor of the modern Internet. In 1963 he co‑developed the first computerized map of Mars for NASA.

Vallée is perhaps best known in UAP circles for his early advocacy of the extraterrestrial hypothesis and, later, for proposing the interdimensional hypothesis—the idea that UFOs may represent phenomena operating outside our conventional understanding of space‑time. His influential “Trinity Hypothesis” (the notion that UFO encounters reflect a control system that has been interacting with humanity throughout history) has shaped much of contemporary ufological thought.

Vallée served as a real‑life model for the character of Lacombe in Steven Spielberg’s 1977 film Close Encounters of the Third Kind. He has authored numerous books on the subject, including Passport to Magonia (1969), The Invisible College (1975), and Trinity: The Best‑Kept Secret (2021). Vallée continues to be a respected voice in the scientific discussion of UAPs, emphasizing the need for rigorous, multi‑disciplinary research.