Here, I will mention some of the most helpful books to study vocabulary for the new (revised) GRE. As you all know, the new GRE has no synonymous and antonymous. The words appear in context; as in text completion and passages. Therefore, as the questioning style changes, the way we study the vocabulary has to change. Mind that you couldn’t avoid studying vocabulary because it is still one of the critical skills the revised GRE tests, though in a slightly different approach. Rote memory doesn’t work anymore. Going through Barron’s word list could be helpful, but not the best approach to tackle the new GRE. You have to shift our attention to those books which offer vocabulary under contexts. Here are a few of of those books that I strongly recommend you to study before you took your GRE.
1. Word master: this is an highly professionally recorded audio book. Since the words are not as challenging as Verbal Advantage and the other books mentioned below, this very good for starting up. They teach you the words with definitions and good example sentences.
2.1100 words you need to know: The words in this books are carefully selected. You will find them very helpful even for your day to day communications. The author teaches the words by interjecting in interesting passages and exercises. A must have for non-natives.
3. Verbal advantage: it has both hardback and audio versions. Verbal advantage is the most comprehensive vocabulary program in English language. The audiobook is amazing. It can take you three or more months to naturalize it, according to your background (you might catch it even in a month, I am not native). It can pump up not only your word power but also your confidence. The person reading the audio book is the author himself. He is a word guru. He teaches you more than 3500words in the audio-book (it comes with a booklet).
4. 30 days to a more powerful vocabulary: a classic guide to the etymology and usage of many English words.
5. Word Power made easy: another classic.
The last two books are somehow similar. They approach the words from etymology perspective; a very good method to teach new words, actually. It is easier to learn the words when you associate them to each other via their etymology.
Most importantly, keep on reading advanced literature, as in New York times Sunday book review, Wall Street journal etc. I found Christopher Hitchens books exceptionally rich in vocabulary and style. I highly recommend his books.