This contribution gives an overview of Einstein's work on unified field theory. It characterizes this work from four perspectives, by looking at its conceptual, representational, biographical, and philosophical dimensions.

The paper analyzes Einstein's path to the General Relativity in the context of its historical alternatives. The main alternatives were constituted by an exclusively field theoretical approach to gravitation and a generalization of mechanics following suggestions by Ernst Mach. It is shown that Einstein succeeded in avoiding the pitfalls of both approaches by suitably combining them. The characteristics and the success of his path to General Relativity are explained by his non-specialist, integrative outlook on the problem of classical physics.