This article discusses the theoretical basis, models and practices of Strategic Human Resource Management (SHRM) and its relationship with business strategy. It evaluates and compares different SHRM models such as Harvard HRM Model, SHRM Diagnostic Model, and Management by Objectives. It also covers HR practices such as performance management, reward, development and learning, and change management. The article includes a case study of Merrill Lynch and examples of companies like Google and GSK.