Dennis McCarthy has published numerous works in the fields of science and Shakespeare studies. He is best known for his discovery that the soldier-scholar-knight Sir Thomas North was the author of plays later adapted by Shakespeare. He is also the "rogue scholar" who is the subject of Michael Blanding's In Shakespeare's Shadow: A Rogue Scholar's Quest to Reveal the True Source Behind the World's Greatest Plays. In February 2018, news of McCarthy’s discovery of an important North-Shakespeare manuscript made the front page of The New York Times, and stories about McCarthy, North, and Shakespeare have appeared in Boston Globe Magazine (cover story), The (London) Times, The Telegraph, The Guardian, The Independent, The Daily Mail, The Los Angeles Times, U.S. News, Philadelphia Inquirer, Slate.com, and generated still other press throughout Europe, Asia, South America, Africa, and Australia.
McCarthy has published two academic books with June Schlueter, Professor Emerita of English, Lafayette College: Thomas North's 1555 Travel Journal: From Italy to Shakespeare (FDU Press, 2021) and A Brief Discourse of Rebellion & Rebels by George North: A Newly Uncovered Manuscript Source for Shakespeare's Plays (D. S. Brewer in association with the British Library, 2018). His first book, Here Be Dragons: How the study of animal and plant distributions revolutionized our views of life and Earth (Oxford University Press, 2009), introduced the subject of biogeography (the intersection of evolution and geography) to the general public. Science News described it as "fascinating and revelatory;" Science Magazine declared, "we will never look at the world in the same way again."
McCarthy has also published papers in the leading journals of geophysics, biogeography, and English literature. His 2007 paper for The Journal of Geophysical Research was the first to provide the correct explanation for the global distribution of continents and oceans and became the subject of a number of news reports in the European press. Der Spiegel Online noted that the "study surprises the professional world."