This present book is focused on firstly, control of non-self-regulating process of various problems associated with the time delay in an unstable process is studied also an attempt is made to compare various approximations. To design a controller direct synthesis method was used.Secondly, "Enhanced performance with PID controllers and lead/lag compensators for unstable processes with time delays" are studied.Thirdly, "Comparative evaluation of decoupling control schemes for MIMO non-square processes are studied three decoupling schemes for MIMO non-square processor" are designed. Finally, we designed a controller for bioreactor process.