Product returns have shifted from a peripheral cost of business to a defining operational and environmental problem. In 2025, retailers in the United States expected roughly 15.8 percent of annual sales, some 849.9 billion dollars in merchandise, to flow backwards through their networks, with online return rates near 19.3 percent. Regulation in the European Union has meanwhile begun treating post-consumer flows as mandated recovery obligations, through the Ecodesign for Sustainable Products Regulation, the Digital Product Passport, and the Right to Repair Directive. This review synthesises advances in closed-loop supply chain (CLSC) research with a focus on returns managed as an instrument of product lifecycle recovery rather than residual disposal. It organises the field around five interacting layers, design, information, network, decision, and market, and argues that the most consequential recent advance is item-level data infrastructure, which makes condition, provenance, and residual value legible at the moment a return is initiated, shifting the central question from where to locate recovery facilities to how to decide, at scale, what each returned unit should become. Persistent gaps include the weak empirical grounding of CLSC optimisation models, the neglect of informal recovery systems, the tension between resilience and circularity, and the near absence of validated methods for establishing whether returns management reduces environmental burden.