This book is a compilation put out by Mr. Anu Garg. If you are not familiar with Mr. Garg, he keeps the "Word a Day" email list. Mr. Gargs love of words shows through his "Word a Day" list and now, this book as well. A great gift for any linguaphiles on your list.
I strongly recommend against buying this book. As someone who can pretty much ace an SAT or any vocabulary test, I can tell you that basically no matter who you are, you will find this book usless and boring. Unless you have a better vocabulary than 99.9% of people (I do), you will not know or ever see the majority of these words (I havent). There are some good ones - less than 10% of them - but if you want to improve your vocaulary, try something else. If you like words that are not even in the dictionary (except maybe Oxford Unabridged), words that never have and never will be used, or words that make you sound so smart that even the smartest 1% of the population wont know what youre saying, you might actually enjoy this book. However, if you dont fit into one of the above catergories: DO NOT BUY THIS BOOK! Try Word Power or Word Smart I and II if you would like to acquire a good vocabulary or sound educated.
I will keep it brief because the title of this book explains its subject matter well. This is a well-written, intriguing little book that begs to be pored over at ones leisure. It is a pleasure to read about obscure words and their origins.