Two memory engines, not one: FSRS-5 schedules cards, FIRe skill trees schedule knowledge - most apps ship only one. Cards come from what you read and hear: select text in PDF or EPUB to translate or card it, OCR for scans, audio paired with SRT subtitles. AI distills a whole book into notes, a mind map and a book-specific assistant you keep chatting with. No account, your own AI key, import Anki .apkg, export packs that keep your progress. Free is feature-complete; Premium only removes ads.