  We give an overview on current experiments on Bose-Einstein condensation
(BEC) in a one-dimensional (1D) optical lattice. We introduce measurements of
ground state, tunnelling and dynamical properties as well as investigations of
atom optical applications and thermodynamical properties. Measurements of the
coherent atomic current in an array of Josephson junctions and the critical
velocity for the breakdown of superfluid motion are discussed in detail.
