At the Denver X-Ray Conference, the topic for the plenary lectures alternates annually between x-ray diffraction and x-ray fluorescence. This year is a "diffraction" year, and the theme is accuracy in powder diffraction. Instead of comprehensive cover- age, such as was attempted at the Accuracy in Powder Diffraction Meeting held at the National Bureau of Standards in 1978, this meeting focuses on recent developments in measurement accuracy of two-theta and intensity. The focus on accuracy, from the practical point of view, is important in a wide range of x-ray diffraction measurements. Accu-...