The phase space structure around L-4 in the restricted three-body problem i
s investigated. The connection between the long period family emanating fro
m L-4 and the very complex structure of the stability region is shown by us
ing the method of Poincare's surface of section. The zero initial velocity
stability region around L-4 is determined by using a method based on the ca
lculation of finite-time Lyapunov characteristic numbers. It is shown that
the boundary of the stability region in the configuration space is formed b
y orbits suffering slow chaotic diffusion.