TQM is a process and philosophy of achieving best possible outcomes from inputs by using them effectively and efficiently to deliver best value for customers while achieving long term organizational objectives. It involves everyone in an organization in a continual effort to improve quality and achieve customer satisfaction. Some key principles of TQM include meeting customer requirements, continuous improvement, prevention over detection, and top management commitment and involvement. Barriers to implementing TQM include lack of management commitment, inability to change culture, and lack of employee involvement and training. Quality gurus like Deming, Juran, and Shewhart made important contributions to the development of concepts like statistical process control, continuous improvement cycles, and an emphasis on management responsibility for quality.