As a plastic that is halfway between common nylons and polyethylene, polyamide 12 (PA12) is an attractive engineering polymer in compact form. Hsu-Hsien Chang et al. on page 14 consider it as a framework material for porous polymeric membranes. The cover image shows a detailed micrograph of the porous bulk of a skinned PA12 membrane fabricated via water precipitation from a formic acid solution at an elevated temperature. Liquid-liquid phase separation and subsequent polymer crystallization lead, upon drying, to the formation of a cellular porous structure. Semicrystalline polymer pore walls exhibit a texture with distinct lamella-type entities.