  This document gives a historical review of the scaling of particles yields
emitted from excited nuclei. The focus will be on what scaling is, what can be
learned from scaling, the underlying theory of why one might expect particle
yields to scale, how experimental particle yields have been observed to scale,
model systems where particle (cluster) yields do scale and finally scaling
observed in the particle yields of various low and medium energy nuclear
reaction experiments. The document begins with a basic introduction to scaling
in the study of critical phenomena and then reviews Fisher's theory which has
all the aspects of scaling and can be directly applied to the counting of
clusters, the most reliable measurement accessible to the experimental study of
nuclear reactions. Also this document gives a history of the various scalings
observed in nuclear reaction experiments and culminates with an estimate of the
nuclear liquid-vapor phase boundary based upon measured particle yields.
