Episteme is a modern, cross-platform e-book and document reader built with Kotlin Multiplatform and Compose Multiplatform. It supports a wide array of formats including EPUB, PDF, MOBI, audiobooks (M4B), FB2, DOCX, ODT, PPTX, and comic archives (CBZ/CBR). The app offers a rich reading experience with paginated and vertical scroll modes, text-to-speech, ink and text annotations, OPDS catalog browsing, cloud sync via Google Drive and Firestore, AI-powered summarization, and extensive customization (themes, fonts, brightness). The codebase is organized into a shared module containing core business logic, models, and policies, with platform-specific implementations for Android (native Compose, Room, WorkManager), iOS (Swift), and Desktop (Compose Desktop, Swing interop). The architecture follows a clean separation of concerns with expect/actual abstractions for platform services, making it a strong example of production-ready KMP application design.