In this paper a method is developed to study the first eigenfunction u
> 0 of the Laplacian. It is based on a study of the distribution func
tion for u. The distribution function satisfies an integrodifferential
inequality, and by introducing a maximal solution Z of the correspond
ing equation, bounds obtained for Z are then used to estimate u. These
bounds come from a detailed study of Z, especially the basic identity
derived in Theorem 3.1.