We discuss unstable nuclei on the proton-rich and neutron-rich side of stability and their properties of astrophysical relevance. The Coulomb barriers in charged-particle captures lead to a cycle pattern which is not existent in neutron-induced reaction processes. They also assure that capture and decay time scales are of similar size. Neutron capture and photodisintegration time scales, on the other hand, are much shorter than beta-decays for high temperatures and neutron densities. Thus, the mechanisms of explosive hydrogen burning or rapid proton capture (rp-process) and rapid neutron capture (r-process) are not fully symmetric in nature. We highlight key features of nuclear reaction patterns, mass and decay properties, which can be used to describe the resulting energy generation and abundances with high precision.This research was suppored in part by NSF grants AST 89-13799, PHY 88-03035, DFG grant Kr 806/1, BMFT grant 06MZ106, and the Alexander von Humboldt foundation. Part of the computations were performed at the National Center for Supercomputer Applications at the University of Illinois (project ybq).