"...Relying on his extensive knowledge of a number of foreign languages, successfully combining the various and diverse available sources, John Jefferson has managed to produce the most comprehensive account of events regarding the Ottoman-Christian conflict between 1438 and 1444 to date. His book will certainly represent essential reading for anyone interested in the research of Ottoman expansion during the 15th century, and it will surely come to be considered as the standard work for the study of the Long Campaign and the Battle of Varna. Because of the way in which it is structured and how the arguments and the story in it are presented, the book will be of interest not only to specialists, who will find a wealth of new material in it, but also to the more casual reader seeking to understand the broader context of the conflict between the Ottomans and Christians in the Late Middle Ages."Emir O. Filipović, Prilozi za orijentalnu filologiju (Contributions to Oriental Philology), Vol. 63, Sarajevo, 2014