Informal is the right way to describe this book. The author basically gets us out for a drink and starts recounting about what he and his colleagues were up to in 50s and 60s.

And with conversations between chemists like these:
“Joe? You know that stuff you sent me to test for thermal stability? Well, first, it hasn’t got any. Second, you owe me a new bomb, a new Wianco pickup, a new stirrer, and maybe a few more things I’ll think of later. And third (crescendo and fortissimo) you’ll have a couple of flunkies up here within fifteen minutes to clean up this (—bleep—) mess or I’ll be down there with a rusty hacksaw blade. . . .” I specified the anatomical use to which the saw blade would be put. End of conversation.
You knew just how crazy it could get.

Now because this is a history of rocket propellants, the book can get technical at times, but nothing that can impede a 21st century reader who knows how to use the Wikipedia.

Hell just an introduction by Isaac Asimov, whom the author knew personally was an excellent incentive to read this book.