The chemical compositions of very metal-poor stars yield direct
information on the onset of early Galactic nucleosynthesis.   
Evolutionary models of low metallicity intermediate-high mass stars 
can generate detailed predictions of abundances returned to the halo 
interstellar medium.  These predictions must be constrained by 
observed abundance ratios in presently surviving halo stars. 
But are the observed abundances accurate enough for this task?
In this talk I will summarize the final results of a long effort to
produce high quality laboratory data for many neutron-capture elements
(Z > 30), and parallel work to improve the accuracy of their abundances
in the solar photosphere and in selected very n-capture-rich metal-poor
stars.  I will also describe early results in a new program to bring the
same scrutiny to the Fe-group elements.  The Fe-peak elements dwarf the
n-capture ones in raw number and in importance for supernova
nucleosynthesis
predictions, but at present their abundances in metal-poor stars are
not extremely well-determined.  I will describe our efforts to cleanly
address this issue.