This study presents a system for shifting Yuseong-gu public libraries from “visible” to “working” specialization. The authors diagnosed library collections, usage patterns, programs, services, spaces, staffing, partnerships, and local contexts, and examined topic suitability via practitioner focus groups, expert consultations, and a citizen survey. Nine of ten libraries had established thematic areas; however, non-book/digital resources, dedicated staff/space, and networks were underdeveloped. The study identifies library-specific themes aligned with core values and visions, and proposes a basic operational framework; two key programs, one standing space, annual resource targets, responsible staff, and regular partnerships. A three-phase plan (2025-2035), supported by inter-library collaboration and shared outcome indicators, offers a reproducible, place-based model for library specialization. This study redefines specialization not as a thematic declaration but as an operational design, and presents a reproducible, place-based model.