Scheduling of jobs on machines can be observed in many real life problems. The book covers up the basic concepts of OR and Scheduling theory. The book focuses on the Flow Shop Scheduling Models in two stage where the objective is to minimize the Idle Time of Jobs. The job block concept in these models have been well thought of. The models considered here are specially structured in the sense that the processing times of both the machines are not on the whole arbitrary but have a definite relationship with one another.