An introduction to some of the techniques used to analyze paintings. Techniques discussed include illumination, x-ray radiography, infrared reflectography, autoradiography, and reactive staining. Paintings discussed in detail include The Present of the Chasuble to St. Ildefonso , The Annunciation by Joos Van Cleve and Rembrandt's Aristotle Contemplating the Bust of Homer . The relationship between the materials and goals of conservation is also discussed.