I find that poking around raw APIs - especially if I'm busy trying to accomplish something else - doesn't often give me enough to figure out what's interesting about a technology. All I need is a few good examples and some explanations and then I'm on my way - and the Pragmatic book starts with the good examples right up front.
It is a beta version of the book, and it still has some typos and funny code examples, and you can tell that Christophe Porteneuve's mother tongue is French with some of the phrasing and word usage - but nothing gets in the way of the raw usefulness of the book.
The biggest deal for me turns out to be in many ways the simplest: the replacement of "document.getElementById('table-contents')" with "$('table-contents')", and a pile of element-specific value retrievers with $F('firstname'). Suddenly, getting stuff out of the DOM isn't a bloated headache, and the size of my code has gone way down. It's interesting how it's taken about a decade for people to figure out where a language needs to be optimized.