How to read a definition, a theorem and a proof. The skill general reading does not give you, taught before the two thousand pages that assume it.
Free to start · adaptive placement finds your level · reviews timed to your own forgetting.
Every idea is taught with motivation and a worked example before the drills, and an FSRS spaced-repetition engine schedules each review for the day its model predicts you would forget it. A short placement check finds what you already know, so you start Reading Mathematics exactly where it's useful.