In recent years, a lot of effort has been put into better understanding the physical processes which lead a sunlike star, at the end of its evolution, to lose its gaseous envelope and die as a slowly cooling white dwarf. The most spectacular phase of this late evolution is the one in which the ejected envelope is made fluorescent by the energetic radiation from the naked stellar core, in which the last thermonuclear reactions take place. These ionised nebulae, historically (and misleadingly) called 'planetary nebulae', are among the most beautiful objects in the Universe, and are the key to understanding phenomena which are relevant to many fields of astrophysics and particle physics.