In this paper. we prove that when the domain B is a two dimensional ball. f
or all small positive epsilon, the solution curve ((lambda, u) of the pertu
rbed Gelfand equation - Deltau = lambda eu((1+epsilonu)) with u/(partial de
rivativeB) = 0 is exactly S-shaped. This settles along-standing conjecture
on the enact number of solutions to this equation. (C) 2001 Academic Press.