  Close binary central stars of planetary nebulae are key in constraining the
poorly-understood common-envelope phase of evolution, which in turn is critical
in understanding the formation of a wide-range of astrophysical phenomena
(including cataclysmic variables, low-mass X-ray binaries and supernovae type
Ia). Here, I present the results of our on-going, targeted search for
close-binaries in planetary nebulae which has led to the discovery of more than
10 new central binaries in just the last few years (almost the same as the
total discovered during the 1980s and 1990s together). This success has been
rooted in the targeted selection of objects for study, based on morphological
features deemed typical of binarity, as well as novel observing strategies
(including the employment of narrow-band filters for photometry to minimise
nebular contamination), both of which are discussed. These new discoveries,
coupled with the painstaking characterisation of both newly discovered systems
and those from the literature, mean that we are now in a position to begin to
probe the physics of the common-envelope phase.
