The text is intellectual snobbery, but the images are fantastic. To be fair, Tufte makes really good points about how to effectively use visuals of all sorts (charts, reports, maps, fonts, etc.) but the tone is pretentious. Tufte believes that one should not talk down to an audience, and he certainly doesn’t here. For example, from page 116: "Multiple versions of these prankish glasses reinforce the perception that what we have here is not merely a one-time lapse but rather a chronic silliness—just as the multiple views of the multiple Watergate defendants intensify the atmosphere of feloniousness." Not exactly Dr. Seuss, eh?
That said, the pictures are so compelling I spent at least an hour just thumbing through the book before starting to actually read it! My favorite chapter was Explaining Magic: Pictorial Instructions and Disinformation Design. The rest of the book is describes how important images are, but this chapter is about magic and the corruption of visual information. Fascinating stuff. The single most compelling image, however, is the visual history of rock and roll presented on pages 90 and 91; I couldn’t find a copy online, but a snippet can be seen in the background here. This diagram grabs my attention each and every time I see it.
Our thinking is filled with assessments of quantity, an approximate or exact sense of number, amount, size, scale.