The article gives a history of how production functions in economics have evolved over time. It talks about how famous functions like the Cobb-Douglas and Constant Elasticity of Substitution were developed, and how they were improved to include things like variable substitution elasticity and biased technical changes. The paper covers different types of production functions and how they were used to study the relationship between inputs and outputs in economics. It also discusses controversies around the role of capital in production functions.