This book deals with the 5S method, which originates from Japan, as an essential foundation for process optimization in manufacturing companies. It demonstrates how this method can contribute to a valuable culture of improvement that offers significantly more than just the creation of clean and orderly workplaces. The first part explains various methods of process improvement and the approach to occupational safety, establishing the connection between 5S, these methods, and occupational safety. The second part illustrates, through numerous practical examples from companies, that 5S is a crucial prerequisite for successful improvement efforts within the organization and the positive impact that consistent implementation of 5S has on the introduction and application of other methods. Thus, 5S significantly contributes to the development of a learning organization that involves employees.