You must understand the process before you can control it and the simplest control system that will do the job is the best.

William L. Luyben (1990)

This chapter presents some novel applications of neural networks in process control. Four different approaches utilizing neural networks are presented as case studies of nonlinear chemical processes. It is concluded that the hybrid methods utilizing neural networks are very promising for the control of nonlinear and/or Multi-Input Multi-Output systems which can not be controlled successfully by conventional techniques.