The content of neutron-capture (trans-iron-peak) elements in the low-metallicity Galactic
halo varies widely from star to star. The differences are both in bulk amount of the neutron-
capture elements with respect to lighter ones and in element-to-element ratios among
themselves. Several well-defined abundance distributions have emerged that reveal
characteristic rapid and slow neutron-capture nucleosynthesis patterns. In this review we
summarize these observed metal-poor star's abundances, contrasting them with the Solar�…