The scientific endeavors of the Middle Eastern studies philologist and South Arabia expert David Heinrich Muller went far beyond disciplinary boundaries. This publication thoroughly examines for the first time the 1898 South Arabia expedition of the Vienna-based Imperial Academy of Sciences which constituted a highlight in his career. It not only focuses on Muller’s achievements for South Arabian studies and his role in this expedition, but also examines his position as a Jewish scholar in the late Habsburg Empire. The ambitious scientific aims of the expedition included the search for inscriptions and the recording of the hitherto barely researched new South Arabian languages Mehri, Shauri and Soqotri, in addition to geological and other natural science investigations. Alongside Muller the German-Swedish count Carlo Landberg was appointed as head of the expedition into the country’s interior due to his good connections in South Arabia. Considerable difficulties during this part of the journey eventually made further movement into the hinterlands impossible and led to the count’s resignation. A final failure could only be averted through the decisive action of Muller who brought the expedition to a successful conclusion through explorations in Socotra. Despite the ill success of the advances into the interior, the achievements made for linguistics and the natural sciences exceeded all expectations. These substantial results could only be accomplished through the research team’s productive collaboration in such a critical situation.