  This work reviews the available experimental information on the pi-pi
scattering lengths, especially the recent near-threshold pi N -> pi pi N data
from several laboratories and the related application of the Chew-Low-Goebel
(CLG) technique well below 1 GeV/c momentum. At this time uncertainties
stemming from non-pion-exchange backgrounds in near-threshold CLG studies
appear to preclude a determination of the pi$-pi scattering lengths with the
desired accuracy of 10% or better.
