The program to formulate a unified theory of the gravitational and the electromagnetic field was widely shared by many theoreticians in the 1920's. The paper will discuss the motivation for this program and some of the approaches that were explored at the time. What was the aim of the program and what were the means that its proponents put to use in order to achieve it? Philosophical considerations about the characteristics of a perfect theory loomed large but were by no means the only factor that determined the unified field theory program.