After graduating from Boston Latin School, Mark earned a BA from Harvard University Magna Cum Laude, and went on to earn a PhD in history from Harvard University and an MLS from the University of Pittsburgh.
Professionally, he was a professor of history at Carnegie Mellon University, editor of the bibliography, "European Americana", and then Curator of Manuscripts at the John Hay Library at Brown University for 25 years until retiring in 2004.
In 1989, his book, "The Works of George Savile Marquis of Halifax", was published by Oxford University Press.
During his retirement he served on the RI Historical Records Advisory Board and was an avid genealogist, unearthing numerous family connections across the world.
He is survived by his children, Amanda and Jonathan Brown; his sister, Jane Stempel; and longtime companion, Joanna Katsune.