Abulafia has published several books on Mediterranean history, beginning with his book "The Two Italies" in 1977; here he argued that as far back as the twelfth century northern Italy exploited the agricultural resources of the Italian south, and that this provided the essential basis for the further expansion of trade and industry in Tuscany, Genoa and Venice. He edited volume 5 of the "New Cambridge Medieval History" and the volume on Italy in the central Middle Ages in the Oxford Short History of Italy; he also edited an important collection of studies of the French invasion of Italy in 1494-5 as well as a book on "The Mediterranean in History" which has appeared in six languages. He has given lectures in many countries including Italy, Spain, Portugal, France, Germany, Finland, Norway, the United States, Dominican Republic, Japan, China, Israel, the UAE, Jordan, and Egypt.