This volume of Measurement Science and Technology contains a Special Feature on Nondestructive Evaluation of Materials. The special feature puts together research articles within the common denominator of nondestructive testing and evaluation (NDT&E) methods, in particular for inspection of composites, semiconductors and metals. This special feature tried to demonstrate the breadth of applications for which one can use nondestructive testing techniques, together with very recent research developments, some clear demonstrations of the method at work in applications and some of the necessary background theory that underpins the basic testing techniques. This special feature was based on the adopted testing methodology and the principles involved, and further sub-classified into optical, thermal, electrical, acoustical, and microwave nondestructive testing methods. These are presented as follows with a brief description of the accepted manuscripts in each sub-section.