Heavy Flavours Leptonic and Semi-leptonic Decays on the Lattice
  We present some results of the {\bf{ELC}} (European Lattice Collaboration) study of leptonic and semi-leptonic decays of heavy-light mesons.   Results on the decay constants $f_D, f_{D_s}$ and $f_B, f_{B_s}$, the semi-leptonic form factors of $D\longrightarrow K (K^*)$ and some preliminary estimates of form factors relevant for the $B\longrightarrow \pi , \rho$ are summarized. The $1/M$ corrections to asymptotic scaling laws are discussed. 
As. Abada