Whorf makes the fascinating assertion, new for his time, that the language we speak, to some degree at least, forces us to orient our view of the world in a certain direction, for example the noun based structure of Indo-European languages forces it into considering the world as made up of interacting fixed parts whereas Hopi doesn't even have a tense system and doesn't consider the past or the future and sees events as either manifest or unmanifest. A completely different way of viewing the world and yet possessing its own internal logic and ability to express whatever is necessary. This is something Whorf stresses throughout and the so-called `primitive' languages of for example, the native Americans, is far from this western perspective. In fact Hopi stands out as being a language ideally suited to the new physics.
Whorf really lives in two worlds regarding his linguistic studies 1. the fascinating metaphysical world of language constructions throughout the world, i.e. the world view generated by these languages and 2. the strict linguistic approach to languages with its own very formal and structured method to analyse languages, see for example the formulaic approach for one-syllable English words in the paper entitled "Linguistics as an Exact Science".
This book is worth it as no doubt the one by Sapir as well.