An author whose books have won literally dozens of awards, and two of his books have involved him directly in policy-making. The National Academies of Sciences named The Great Influenza: The story of the Deadliest Pandemic in History (2004), his study of the 1918 pandemic, the year’s outstanding book on science or medicine, and he was a member of the initial working group which developed recommendations for pandemic preparedness and response. He also served on the federal government's Infectious Disease Board of Experts and has advised the private sector as well as federal, state, and World Health Organization officials on influenza preparedness and risk communication.

The Society of American Historians named his earlier book Rising Tide: The Great Mississippi Flood of 1927 and How It Changed America (1997) the year’s best book of American history, and in 2005 the New York Public Library named it one of the fifty best books of all kinds, whether fiction, non-fiction, or poetry, in the preceding fifty years. In 2006 the National Academies of Sciences invited Barry to give the Abel Wolman Distinguished Lecture, which annually honors contributions to water-related knowledge; he is the only non-scientist ever to give that lecture. After Hurricane Katrina, the Louisiana Congressional delegation asked him to chair a bipartisan working group on flood control, and from 2007-2013 he served on both the board which oversees levee districts in metropolitan New Orleans and the Louisiana Coastal Protection and Restoration Authority, which develops and implements the hurricane protection plan for the state. An initiative he launched on hurricane protection has been the subject of articles in publications ranging from The Economist and Der Spiegel to The New York Times Magazine, and he has served on the advisory board for M.I.T’s Center for Engineering Systems Fundamentals.

A guest on every broadcast network in the United States, the BBC, and other foreign outlets, he has also contributed to award-winning television documentaries and his articles have appeared in scientific journals such as Nature and the Journal of Infectious Disease as well as The New York Times, The Washington Post, Fortune, Time, Newsweek, and Esquire.