Readwise is a reading companion that imports highlights from Kindle, Instapaper, Apple Books and other sources into a single searchable library. It is designed for readers, students, and lifelong learners who want to revisit and retain the key ideas from their books. What sets Readwise apart is its spaced‑repetition system that surfaces your best highlights at optimal intervals, and its ability to tag, note, and connect ideas across all your reading. The result is a personal knowledge base that grows over time.