[en] The author discusses which indirect evidence for octupole deformation can be drawn from the nuclear ground-state properties. A first indication of octupole effects in the ground state came from the masses around /sup 222/Ra. The systematic deviations of calculated masses from the experimental values were removed by the inclusion of the octupole degree of freedom into deformed shell-model calculations which then resulted in reflection-asymmetric equilibrium shapes for the nuclei with proton numbers between Z = 86 and 92 (i.e. Rn and U) and neutron numbers between N = 130 and 138. The most detailed information about the nuclear ground states emerges from laser spectroscopy experiments yielding the spins, the magnetic dipole and electric quadrupole moments, and the variation of the mean square nuclear charge radii from the measurement of atomic hyperfine structures and isotope shifts. More generally, the technical realization of particle detection of on-line oriented isotopes opens also new avenues for systematic studies of weak interaction (β-decay of mirror nuclei, e.g. /sup 17/F as reported at this conference) and nuclear penetration effects (conversion electron angular distributions)