This book provides essential information on various types and methods of measurement, inspection, and testing, as well as the classification of measuring instruments. It outlines the procedures for conducting tests during product certification. The text includes a classification of measuring devices for electrical and mechanical quantities, with a particular focus on instruments that measure geometric dimensions, displacements, and control of flatness and shape of objects. It describes the construction, operating principles, characteristics, and applications of electromechanical, electronic analog, and digital instruments, along with methods for measuring electrical quantities. Designed for university students enrolled in full-time and part-time programs, specializing in Quality Management (code 220501) and related fields (code 221400).