The large majority of all stars in the Universe that have left the quiescent central hydrogen burning phase, i.e., the main sequence, will reach their final evolutionary stage as stars on the asymptotic giant branch (AGB). This will also happen to our own Sun in about 8 billion years from now. An AGB-star is a cool, luminous, and pulsationally unstable red giant star. It will gradually develop an intense wind that removes material from the surface at an increasing rate as the end is approached. This will have a profound effect on the evolution of the star, and it will eventually terminate its life as a star. Furthermore, the wind also carries the results of internal nuclear processes, activated during the AGB evolution, and hence contributes to the chemical evolution of the cosmic gas. The mechanism(s) behind the mass loss is not yet identified, but the regular pulsations of the star and the formation of molecules and microscopic dust particles in its atmosphere are believed to play a major rôle. When the `star' leaves the AGB the mass loss appears to change its characteristics (less material is ejected, but at much higher velocities), and the surface temperature increases rapidly. The interaction of the fast post-AGB wind and the AGB wind, and the increasing ionizing flux produces a planetary nebula (PN). The research at Stockholm Observatory centres on the AGB mass loss and the formation and evolution of PNe. This presents an interesting astrophysical phenomenon, where an intricate interplay between different physical and chemical process takes place.