This is not a dictionary, a thesaurus, or a book of formal etymology. So, what is it? Well, it takes the word lover on a tour of approximately 1,500 words. We get to find out not only a definition of the word, but its history. How it came to be. Yes, there is some etymology (study of word origins) in this, but the way a word comes to mean what it does can take surprising turns that its origins do not explain. (Also, within some of these histories, the authors provide words of similar origins and histories, so it really is more than 1,500 words.)
While you can use this book to look up words, there are so relatively few that you will more likely miss more often than you will hit. What the book is really for is to fill a few extra minutes with a tour of something fascinating and to learn something you probably did not know. If you just sit down for hours reading many pages of the book you will actually not remember all the things you should. So, it is better to dip into this book frequently for short periods and think about the few words you read about and commit their history to memory rather than pushing your way through hundreds of pages that will evaporate the moment you close the book.
Quite an interesting resource.