Planetary nebulae, glowing shells of ionized gas, are the spectacular products of the evolution of low- and intermediate-mass stars. For astrophysicists, they are important laboratories for the understanding of atomic, molecular, dust, and plasma processes in different cosmic environments; they enable the exploration of the fundamental physics of single and binary star evolution including nucleosynthesis, rotation, mass transfer and loss, and magnetic fields; and they help trace stellar populations, the kinematics, and chemistry of galaxies including our own galaxy, the Milky Way. This volume...