Information on the properties of woods either the physical or the mechanical properties are important for construction and industrial purposes. There are two types of measurements in examining wood properties, namely destructive and non destructive. Mechanical properties of wood are mainly measured using destructive method such as bending test, tensile test, etc. Non-destructive testing (NDT) techniques applied in determining the properties of wood and wood product although valuable are still associated with great amount of uncertainties. The most common methods applied are the microwave, ultrasonic, impact and resistant method. The book reported the use of Parallel Plate Electrode System (PPES) and Capacitor Probe (C-Probe) system to evaluate the properties of wood by analysing the dielectric constant of the material. The PPES and C- Probe is also being applied as inspection techniques to locate damage and decay in timber members in order to maintain the structural performance.