In that case, ∂ is not δ.
Gotcha. Found "dee" in my cheat sheet. Thanks for the heads-up.
There's no way the listener is going to have a happy experience with this book if they're driving. The illustrations and charts are constantly referred to. And since those are only available as PDFs, it's not a wind-in-your-hair kind of experience. The days when I'd get a book like this and have to render all that into actual language are over. (Used to have a studio near CalTech. Made for some looooong lunches. Also, lots of time with the authors.) The price point on audio-book production has dropped to where it's easier to just pump 'em out and pray. That's a top down thing. On the plus side, lots of books. On the negative side, this kind of quandry.
Keeping it as simple as possible is always the best bet in this environment. But it's still better to get it right-ish