This article aims to show the mathematical contexts out of which emerged Solow's 1957 article “Technical Change and the Aggregate Production Function.” In particular, it seeks to provide some understanding of its most striking feature, namely, the highly aggregate level on which technical change is discussed and the simple way in which it is represented. The approach is similar to Weintraub's (1991) contextualization of Samuelson's Foundations of Economic Analysis (1947), but it will map out the two mathematical contexts in which Solow's 1957 article can be located. Samuelson's concepts of stability provided Solow the tools for the aggregation of technical change. However, Samuelson's concepts were defined in relation to static equilibrium and not to growth. To arrive at his 1957 representation of technical change, Solow successfully applied P. H. Leslie's concepts and tools of population mathematics. The main mathematical concepts around which this development is described are eigenvalue and eigenvector. It is by the use of these two concepts that aggregation of input-output tables was made feasible.