Planetary Nebulae: Standing at the (Astrophysical) Crossroads

Planetary nebulae stand at the intersection of a number of fundamental lines of investigation in contemporary astrophysics, including the late evolution of and mass loss from intermediate-mass stars; the (resulting) enrichment of the interstellar medium in the products of intermediate-mass stellar nucleosynthesis; the origins of white dwarfs and interacting binary systems involving white dwarfs; photoionization and wind-shock processes; and high-energy irradiation of molecular gas and dust (among many other topics). I will describe how planetary nebulae provide unique insight into this diverse array of astrophysical processes, and highlight what we are learning, and might stand to learn, from ongoing and future observational and theoretical investigations of planetary nebulae.