James Maxwell Bardeen (May 9, 1939 – June 20, 2022) was an American physicist, well known for his work in general relativity, particularly his role in formulating the laws of black hole mechanics.

That same year, he co-authored the watershed paper "The Four Laws of Black Hole Mechanics" with Stephen Hawking and Brandon Carter during a meeting held at the École de physique des Houches.

Later that year, Bardeen theorized the doughnut shape and size of a black hole’s "shadow", which was later popularized by the observations of Messier 87 by the Event Horizon Telescope.

Together with Michael S. Turner and Paul Steinhardt, he published a paper in 1982 detailing the way submicroscopic fluctuations in the density of matter and energy in the early universe would bring about the arrangement of galaxies seen in the present day.

In a 2020 interview given to Federal University of Pará in Brazil, Bardeen recalls his journey as a physicist, his father's influences on him, his experiences as a doctoral student of Richard Feynman, and working with Stephen Hawking.