Orbifoldes, vari\'et\'es sp\'eciales et classification des vari\'et\'es K\" ahl\'eriennes compactes

This text is an introduction to math.AG/0110051 (to appear in Ann. Inst. Fourier), and describes a canonical decomposition of compact K\"ahler manifolds $X$ first by means of their "core", the unique fibration on $X$ with fibres special, and orbifold base of general type. Being special means that there does not exist a fibration onto an orbifold of general type. The core is next decomposed into a tower of fibrations with all orbifold fibres either with $\kappa=0$, or rationally generated (a weak version of rationally connected).