This work presents the time domain approach to modern process control, which is designed to lead to improved performance and operations. It covers such topics as model predictive control from an optimal control point of view, the use of state and parameter identification for implementation of optimal adaptive control, a variational approach to development of necessary conditions for defining optimal control problems and the treatment of both regulatory control and time optimal control for industrial processes. Practical examples are given throughout to illustrate theoretical concepts. MATLAB, the software package that enables the solution of many optimal control problems, is used for the solution of many text examples. Computational issues, as well as interpretation of results, are stressed.