This repository is a CLI tool for translating books (EPUB, TXT, PDF, SRT, Markdown) into bilingual versions (original + translation side-by-side) using large language models (OpenAI, Anthropic, Gemini, etc.) and free machine translation engines. It supports multiple translation backends, a provider configuration system, and a PDF-to-EPUB pipeline using docling for PDF extraction and Pandoc for EPUB export. The architecture is modular: loaders parse input formats, translators handle API calls with session context and capability probing, and a pipeline orchestrates PDF-to-EPUB conversion with figure rendering and classification. Key entry points are `make_book.py` and the installed command `bbook_maker`. The tool includes features like plan mode for selective translation, glossary support, resume, progress bars, and Docker support. It has extensive tests covering CLI contract, loaders, translators, pipeline stages, and documentation. External dependencies include LLM APIs, docling, pypdfium2, Pandoc, and various SDKs. The codebase demonstrates careful engineering decisions around capability degradation, session compaction, glossary learning, and structured output ladder. It is a well-maintained application with active development and low technical drift.