There are many wonderful books on/of data visualization, and if you work in data, you probably have a few (hopefully more than just that one). You should probably get more.
As your collection grows, consider that the next great book to inspire the chartmaker in you -- to further you on your journey to master the craft -- may not be a treatise on chart types or data storytelling, but something possibly even cooler: A Comic About Comics.
These are just the ones I own. You really can't go wrong with any of them. And even if you have no interest in data viz, this Comics About Comics genre is still a fantastic mind-expanded set of books. This books are really special: they're formally inventive but personal and emotional in their own ways. They provide a wonderful set of boxes to think outside of.
I discovered Scott McCloud's work in 2018, when he was interviewed for an episode of the design podcast 99% Invisible.
That conversation -- but especially his 1993 classic Understanding Comics which I read right afterwards -- completely blew my mind. There have been less than a handful of times in my career where I felt that lightbulb above my head go on with anywhere near the wattage of when I digested Understanding Comics.
I walked away from Understanding Comics with this incredible insight that data visualization was really a form of comics ("sequential art" if you're worried the person you're talking too thinks "comics" is a dirty word). Charts -- and especially sequences of charts to make things like dashboards or powerpoint presentations -- very definitely count per McCloud's definition:
Juxtaposed pictorial and other images in deliberate sequence, intended to convey information and/or to produce an aesthetic response in the viewer.
At that point in 2018, I had been a data person for several years, always making charts to understand and communicate things both professionally and recreationally for many years. I had some successes: charts that helped my colleagues make decisions, charts that made cool nerds on tumblr chuckle, even a few that I didn't think were hideous. I didn't yet have a full bookshelf of data viz books, but I had more than one (the first I bought was indeed that one). Despite not having much academic training in it, I felt like I understood visualization pretty well at that point, but Understanding Comics made clear how limited by understanding was (and still is). Even more so than the grammar of graphics: to me personally this idea of Charts Are Comics has been the most powerful aha moment in my "career" as a chartmaker.
If you've read Understanding Comics and got something out of it, I'd encourage you to keep going with McCloud's work. Although 1996's Making Comics did not quite inspire me to start making comics, it has great lessons about composition and visual storytelling. 2000's Reinventing Comics in particular had a lot of resonance for me, as someone who's sequential art (charts) is both made and consumed through screens and computers.
And just this week, Scott McCloud released another Comic About Comics: The Cartoonists Club with Raina Telgemeier. Aimed at younger readers, it embeds the most important ideas from Understanding... and Making... and into a narrative about middler schoolers finding their voice and their people. Understanding Comics never brought me to tears, but I needed a kleenex after finishing The Cartoonists Club.
While I hadn't considered the relationship between charts and comics until 2018, Many others had made the connection and I just wasn't paying attention. McCloud had spoken at the data viz conference Tapestry in 2013, and Moritz Stefaner (data viz maker and discusser extroidinaire) interviewed McCloud in 2017 for the Data Stories podcast. Also in 2017 in academia, Benjamin Bach worked with Nathalie Henry Riche, Sheelagh Carpendale, and Hanspeter Pfister to publish The Emerging Genre of Data Comics (which itself is a Comic About Comics!). And in 2016, comics professor Nick Sousanis gave a Keynote at Tapestry.
It is reductive to call Unflattening a Comic About Comics: it's definitely a comic, but it's about something a little bigger and a lot more cerebral than McCloud's work (it's a PhD dissertation). It's hard to pin down exactly what to call that (the shapeliness of ideas?). That written words are insufficient to describe the complexity of the topic is another thing the book is kind of about.
Unflattening is also a compositional feast: pages flow in all sorts of directions. Every spread maps complex and abstract things to the two-dimensional page in ways that befit the nonlinearity and high dimensionality of those abstract spaces. Much of the hard work of data viz is making invisible abstract things tractable in two dimensions, and Unflattening contains lesson after lesson in it.
RJ Andrews deserves a shout-out. RJ recommended Unflattening to me at the Tapestry conference in 2018 (I gave my own brief talk at that Tapestry, invigorated by discovering Understanding Comics at the beginning of the year). If you don't have a data viz bookshelf yet, I can safely say Andrews's newly remastered Info We Trust is the perfect place to start (way better than that one). RJ's book is of what it's about in the same way all these wonderful Comics About Comics are. RJ also has a wonderful write-up that covers this very topic: "Books without data for the data professional" that includes both Unflattening and Understanding Comics.
What It Is, like McCloud's classic, is also about understanding comics, but it's form and content differ dramatically. While McCloud explicates the conventions of comics with a focus the prototypical grid of rectangular panels. Barry is more interested in asking than answering, and her work is -- gloriously -- too untidy to fit into little boxes. Even compared to heady academic work of Unflattening, What It Is was maybe the most challenging read for me of any of these comics. It's not formless, but it's far from the rectilinearity of most comics I read. All these books are great for leaving on your coffee table, and leafing through random pages, but What It Is works particularly well for this.
Barry's Making Comics had a magical impact on me: It actually got me drawing! I didn't work my way through the whole book, but I tried a several of the exercises. And for about two months in 2020, I drew a self-portrait on a index card every day (they're hideous and I'm so proud of them). But even if you can't find to courage to draw, Making Comics is worth it for how she grounds the craft in modes we all learned as children.
So read some books, bust out that pen and paper, make some charts, make some comics, making something else.