This volume is an essential handbook for anyone interested in performing the most accurate spectrophotometric or other optical property of materials measurements. The chapter authors were chosen from the leading experts in their respective fields and provide their wisdom and experience in measurements of reflectance, transmittance, absorptance, emittance, diffuse scattering, color, and fluorescence. The book provides the reader with the theoretical underpinning to the methods, the practical issues encountered in real measurements, and numerous examples of important applications.