A mediated resource‑sharing mechanism by which libraries lend and borrow physical or digital materials among institutions to fulfil patron requests, governed by interinstitutional agreements, copyright and licensing constraints, and operational procedures for request, delivery, return, and recordkeeping.

Principle

Interlibrary loan extends local access by leveraging cooperation across institutions while remaining subject to the legal and contractual limits that govern lending, copying, and digital delivery; each transaction reallocates temporary custodial use rather than necessarily transferring ownership.

Demonstration

Illustrative scenario: Situation — a patron requests a journal article not held locally. Recognition — staff search consortial catalogues and identify a lending library. Action — a mediated request is sent, the lending library supplies a scanned article under document delivery terms, and the item is delivered to the patron with appropriate usage and retention notes. Consequence — the patron obtains the content while both libraries record the transaction and respect copyright/licence constraints.

Misapplication

Assuming that because a library can borrow a physical item it may freely digitize and distribute it to patrons; the semantic error is conflating temporary loan rights with rights to reproduce or provide unrestricted digital access.

Consequence

ILL increases user access to materials beyond local holdings but imposes administrative overhead, potential costs, turnaround delays, and the need to track compliance with lender conditions and copyright; expanded ILL can reduce redundant local acquisitions but may shift costs and risks across institutions.

Reversal

When legal restrictions, donor terms, or collection policies prohibit lending (e.g., unique special‑collection items) or when licences forbid interlibrary digital distribution, ILL cannot supply access even if an item exists elsewhere; consortial perpetual access agreements or electronic resource licences may provide access paths that supplant ILL.

Boundary

Clearly within — a mediated request that obtains a physical loan or a single‑article scan under document delivery rules from another library. Boundary case — resource sharing through consortial licence entitlements where access is governed by subscription rather than loan. Clearly outside — informal, unrecorded transfers between individuals or direct purchase of digital copies by patrons without institutional mediation.

Semantic Tension

Access/Equity ↔ Rights/Compliance (maximising patron access through sharing vs adhering to copyright/licence and lender restrictions); ILL operations must reconcile service goals with legal and interinstitutional obligations.

Synthesis

Interlibrary loan operationalizes cooperative access: it temporally allocates materials across institutional boundaries to meet user needs while navigating legal, contractual and logistical constraints rather than replacing local collection strategy.