  We describe the absolute retracts for the following classes of finite
lattices: (1) slim semimodular lattices, (2) finite distributive lattices, and
for each positive integer $n$, (3) at most $n$-dimensional finite distributive
lattices. Although the singleton lattice is the only absolute retract for the
first class, this result has paved the way to some other classes. For the
second class, we prove that the absolute retracts are exactly the finite
boolean lattices; this generalizes a 1979 result of J. Schmid. For the third
class, the absolute retracts are the finite boolean lattices of dimension at
most $n$ and the direct products of $n$ nontrivial finite chains. Also, we
point out that in each of these classes, the algebraically closed lattices and
the strongly algebraically closed lattices are the same as the absolute
retracts.
  Slim (and necessarily planar) semimodular lattices were introduced by G.
Gr\"atzer and E. Knapp in 2007, and they have been intensively studied since
then. Algebraically closed and strongly algebraically closed lattices have been
investigated by J. Schmid and, in several papers, by A. Molkhasi.
