Regular cells can be reprogrammed to make iPSCs or induced pluripotent stem cells through the enforced activation of genes recognized as master regulators of pluripotency. This reprogramming occurs gradually over a period of several weeks. On completion of this process, these master regulators induce a change in the expression of an entire network of genes, replacing the features of differentiated cells with features associated with the pluripotent state. The process of reprogramming regular cells to make iPSCs essentially reverses the development process.