Not a how-to but a history: how the web's formats and practices came to be, and which of them kept working as everything around them changed. Keith's claim is that the durable part is the idea, not the code — HTML's fault tolerance, CSS's cascade, the three-layer model where a page works before the script arrives — and that a site built in those layers is resilient the way a well-made building is.
Read it for the argument behind two of this garden's own rulings: semantics before visuals, and progressive enhancement as the base layer rather than a fallback. The glossary entries for web standards, progressive enhancement and HTML lean on it.
Seven chapters, an evening's read, free at resilientwebdesign.com.