The main aim of this Special Issue was to present the current state of research on the subjects of the theory, modelling, monitoring, and control of the operation of technology systems and processes, along with the research and diagnostics of manufacturing systems and process operation. The contributions focused on the manufacturing research, operation reliability, and diagnostics of machines; the inspection, measurements, evaluation, and diagnostics of production quality in technologies of standard and progressive machining; reversible engineering; 3D printing; pressure die casting; injection moulding; EDM; AWJ cutting; etc., which are used for the advanced processing of materials and various kinds of technological applications.