The shape and shaping of proto-planetary nebulae

While AGB stars display spherical shapes and winds, planetary nebulae appear asymmetric. By studying proto-planetary nebulae (PPNs), the transitional objects between these two stages of stellar evolution, we can learn about when and how these asymmetric shapes develop. We describe in particular our HST imaging studies of PPNs in the visible and near-IR. They commonly reveal a bipolar morphology, in some cases with circumstellar, concentric arcs and in one case with a visible collimating disk. Mechanisms for shaping the nebula are reviewed, and the negative results of a radial velocity study to search for binary central stars of PPNs are discussed.