Liquid-scintillation techniques allow counting (detection and quantification) of nonpenetrating alpha and beta radiation in ways that are potentially more accurate and reproducible and are often easier than other methods. When the radionuclide is in homogeneous true solution in an appropriate organic liquid containing a compound (fluor) that produces light when excited by ionizing radiation, every ionizing event that produces a quantity of light sufficient to be detected by the multiplier-phototube is recorded. For alpha radiation in a 10- × -75-mm culture tube, this is virtually 100% (99.7%) of the events. Historically, the advantages of liquid scintillators for beta counting have been exploited because self-absorption problems for some of these nuclides are so severe in other counting methods that these methods are of limited usefulness. The use of liquid scintillation for alpha counting and spectrometry has been much less employed because other usable methods were developed, because both beta and gamma radiation interfere with alpha counting in liquid scintillation, and because equipment and methods to take full advantage of the capabilities of liquid scintillation in alpha counting and spectrometry have not, until recently, been readily available.