  Let L be a restricted Lie algebra over a field of positive characteristic. We
survey the known results about the Lie structure of the restricted enveloping
algebra u(L) of L. Related results about the structure of the group of units
and the symmetric and skew-symmetric elements of u(L) are also discussed.
Moreover, a new theorem about an upper bound for the Lie nilpotency class of
u(L) is proved.
