Throughout his life, Dubs researched and published on a wide range of topics in
Chinese philosophy and history. In the mid-1930s he was commissioned by the
American Council of Learned Societies to undertake the work for which he would become best known, a translation of
Ban Gu's
Han shu. During 1934-37, Dubs worked on the translation assiduously with three Chinese collaborators, Jen T'ai, C.H. Ts'ui, and P'an Lo-chi. They produced a copiously annotated three-volume translation of the "Annals" section of the
Han shu (chapters 1-12) and the three chapters (99A,B&C) devoted to
Wang Mang, published under the title
History of the Former Han Dynasty (Baltimore, 1938–55). The first two volumes were awarded the coveted Prix
Stanislas Julien of the
Académie des Inscriptions et Belles-Lettres. Two companion volumes, including a prolegomena and a glossary were planned. Thus,
Qian Han shu (Wade Giles ''Ch'ien Han shu'') 前漢書 was rendered Ts'ien2R Han4SU-shu1WE. Although he represented his system as a variation on the widely used
Wade Giles romanization, the field declined to adopt his "Wade-Dubs" system. Indeed, it was his insistence on using the system for the remaining volumes of
History of the Former Han Dynasty that prevented them from being published. Another direction Dubs' interests took him was the pursuit of
contacts between Han China and the Roman empire. He wrote several articles on the subject, culminating in the controversial
A Roman City in Ancient China. This work purported to show that a
Roman legion that had been part of the army of
Marcus Licinius Crassus defeated at the
Battle of Carrhae in 53 B.C. had settled in
Northwestern China. The defeated legion, Dubs speculated, had been relocated further east by the victorious
Parthians, for whom they fought in a battle against the Han. Defeated again, they were settled at a place called
Liqian located in modern
Yongchang County,
Jinchang,
Gansu province. Although this story has been seized upon by enthusiastic Chinese of the area and non specialist Westerners, at least two eminent Chinese authorities have shown that the notion has serious shortcomings. ==Later teaching and activities==