Observations of binaries in AGB, post-AGB stars and Planetary Nebulae

In recent years, many observational studies have revealed that binaries play an active role in the shaping of non-spherical planetary nebulae. We review the different studies that have led to direct or indirect evidence for the presence of binary companions during the Asymptotic Giant Branch, proto-Planetary Nebula, and Planetary Nebula phases of evolution. We also discuss how these binaries can influence stellar evolution, and possible future directions in the field.