in the far-IR to date (the beam size of several to a few tens of arcsec; e.g., @ueta06 [@su07; @vanhoof10; @vanhoof13; @cox11]). The new far-IR window has not only given access to the bulk of the matter in the farthest reaches of PNs, but also permitted us to probe the interacting boundary regions between the PN haloes and ISM, spawning new insights into the processing of the mass loss ejecta as they merge into the ISM (e.g., @wareing06 [@sabin10; @zhang12]).

Among these recent far-IR opportunities, those provided by [*Herschel*]{} are unique: [*Herschel*]{} allows simultaneous probing of the multiple phases of the gaseous components in PNs via far-IR ionic, atomic, and molecular line emission. The [*Infrared Space Observatory*]{} ([*ISO*]{}; @iso) made detections of far-IR lines from about two dozen PNs [@liu01] and another two dozen PN progenitors and other evolved stars [@fong01; @cc01]. However, the [*ISO*]{} apertures typically covered most of the optically-bright regions of the target objects,[^2] and therefore, the previous [*ISO*]{} spectroscopic analyses were usually performed in a spatially-integrated manner.

[*Herschel*]{}’s spectral mapping capabilities allow us to look for variations of line/continuum strengths as a function of location in the target nebulae, so that the spatially resolved energetics of 