If you're curious enough to read a 900 page book containing very accurate information about the specific processes that occur when preparing most foods then On Food and Cooking by Harold McGee[0] is the book for you. It's not for everyone but I give you my guarantee as an internet stranger that you'll love it.
I have "Ratio: The Simple Codes Behind the Craft of Everyday Cooking" and was unimpressed. The idea of thinking in ratios is useful, but not the oversimplification to a few prototypes. You could look at a recipe as something with a whole bunch of ratios and valid ranges, and document the effects of variation and so on. It would be a much bigger book and not "this little volume contains all the secrets to everything".
Edit: by the way, what is with the Amazon pricing? Hardcover is $25; "mass market paperback", new is $901! Not to mention, the featured hardcover price is noticeably more than the specific new hardcover price of $20.
Amazon sellers use a lot of automated bots which automatically adjust their prices in apparent competition with each other [1]. You can find used copies of rare books that are priced at thousands of dollars. In this particular case, you're looking at a Chinese edition, which is presumably out of print.
On Food and Cooking is a fantastic book, by the way. A real classic that every food enthusiast should have on their shelf. I recommend the hardcover version.
I wasn't quite as unimpressed with ratio as you seem to have been, but I do think that there is really enough information there for a pamphlet not a complete book. Being able to think of doughs and batters as a state-space of flour/fat/liquid is conceptually useful. In general you might pick up on this from experience cooking, but it's rarely elucidated.
[0] https://www.amazon.com/Food-Cooking-Science-Lore-Kitchen/dp/...