The author, who is employed by the United States Secret Service (USSS), Technical Division, gives several case studies of the use of thin layer chromatography (TLC), x-ray fluorescence (XRF), and other analytical techniques to detect counterfeit currency and altered documents. Determination of the age of papers and inks is critical to most investigations. Author stresses the importance of reliable standards. The USSS has the largest collection of writing inks in the world and this resource is invaluable in the agency's work. -- AATA