The escalating cost of academic textbooks in India presents a significant financial burden to engineering students, many of whom purchase books for a single semester only to leave them unused thereafter. This paper presents ReBook, a full-stack, location-aware web platform that facilitates the buying, selling, and donation of second-hand academic books among students. The system employs Java Spring Boot for the backend REST API, MySQL 8.0 for persistent storage, and a JavaScript single-page application for the frontend. Key innovations include GPS-based distance sorting using the Haversine formula, WhatsApp seller integration, a pincode-level hyper-local search filter, and an AI-powered camera-based book condition detection module built on the Claude API (Anthropic). All ten planned feature modules were implemented and verified functional across Chrome, Firefox, and Android mobile browsers. ReBook directly addresses the affordability and sustainability challenges of academic publishing for students across India.