This book includes the study about a new developed Hybrid EWMA control chart based on Product- Difference Estimator of Mean (PD-HEWMA) using Auxiliary Information which performs better than all other existing/traditional control charts. PD-HEWMA control chart using the auxiliary information for efficient monitoring of process mean. The control chart constants have been determined using Monte Carlo Simulation for various values of correlation coefficients. The choice of correlation coefficient has a significant effect on the value of control chart constants which are used in the construction of the proposed PD-HEWMA chart. The performance of the proposed chart is assessed with respect to the average run length out-of-control situations for different values of correlation coefficient and sample sizes.