Yahalom is the author of numerous books and articles on Hebrew poetry, from Byzantine Palestine (5th century CE) to the early modern period. Much of his work explores the connections between Hebrew poetry and the literature of the other groups living in the same time and place, for example, the link between piyyut and Syriac and Greek Christian hymns; between Hebrew poetry from Spain and the emerging romances in European languages; and between early modern mystical Hebrew poetry in the Ottoman Empire and Turkish songs. He also has written extensively about the bilingual (Hebrew and Arabic) culture of Judah Al-Harizi.