The purpose of this paper is to present a rapid survey of the statistical properties of spectra, using both atomic spectral data and nuclear spectral data. In many cases, only one kind of relevant data exists; for example, very little is known about atomic‐particle transition‐probability data, so in such areas we must confine our attention to nuclear data. When both atomic and nuclear data are available, we have tried to select those data which are usually not treated according to the general approach of this paper. Throughout our discussion, then, we will be mainly emphasizing analogies and the manner of handling different sorts of data according to the spirit of this paper.