Human resource management involves planning, organizing, directing, and controlling organizational human resources to satisfy organizational, individual, and societal needs. It includes activities like recruitment and selection, training and development, performance management, compensation and benefits, and labor relations. Key aspects of HRM are human resource planning to forecast needs, developing consistent HRM components, using valid selection tools, providing training and development programs, conducting performance appraisals, establishing competitive pay and benefits, and managing labor relations. Legislation like the Railway Labor Act, Wagner Act, and Taft-Hartley Act have impacted the development of HRM and union relations over time.