Ask HN: Best pedagogical material on any subject matter?

In the spirit of the "How Do You Learn?" thread - what are you favorite examples of well done textbooks/pedagogical material, in any subject?

Looking for works that people believe weaves natural narrative with explicit "learning material" in the best way. It could be entertainment, quality of writing, organization - I suppose there is no limit to the strategy of making new material both accessible and smooth. Feynman~ish comes to mind here!