[en] This paper discusses several recent advances toward a deeper understanding of the still unknown astrophysical site for rapid (r-process) neutron capture nucleosynthesis. The physical constraints on the r-process from the input nuclear data are highlighted and the particular importance of the recent measurements of beta-decay lifetimes along the r-process path is discussed. Astronomical observations of s- and r-process elemental abundances on metal poor halo stars are also discussed, in the context of models for the galactic chemical evolution of heavy-element abundances, as a constraint on the nature of the r-process. On the basis of these constraints it is suggested that the most likely source for the r-process may be from the ejection of core material from low-mass type II supernovae. 27 refs., 1 fig