Zinsmeister has conducted in-depth research on the inventive power and importance of science philanthropy, which has powered innovations ranging from the world's greatest telescopes to medical breakthroughs like blood typing; organ transplants; vaccines for polio, yellow fever, and many other diseases; fundamental genetic discoveries; and seminal brain research; along with many other discoveries. He has uncovered much nearly unknown American philanthropic history, including essays on medical research, the importance of anonymity to private giving, even the existence of "national-security philanthropy" in the U.S.—by which donors have made crucial contributions to defense of the nation. He has analyzed who gives most to charity in the U.S., and tracked the rise of donations by Americans for overseas development work. He has catalogued the private philanthropy that was crucial to creation of the state of Israel.