In our quest to understand radiation damage in materials, it is vital that we characterize radiation sources in terms of neutron flux and spectra as well as the more-fundamental displacement damage, gas production, and transmutation rates. Such data are crucial to correlations of materials-property changes in different environments and to predictions of materials performance in inaccessible environments, such as fusion reactors. Dosimetry techniques have been developed to measure the neutron flux and spectra in diverse facilities including thermal, fast, and mixed reactors, T (d,n) and Be (d,n) accelerator sources, and high-energy spallation sources. Displacement-damage cross sections have been calculated for 36 elements spanning the periodic table. All of these exposure parameters can now be routinely measured with 10 to 15% relative accuracy at all existing radiation-effect facilities. 4 tables.