Some useful "word power" books

Here are some books that I've come across recently that might be useful for those who want to build their knowledge of word-power and etymologies:

1. Norman Lewis, Word Power Made Easy
2. Medical Terminology For Dummies (2nd-Edition)
3. Lewis Stiles, The Anatomy of Medical Terminology
4. Verbal Advantage: Steps to a Powerful Vocabulary
5. Barron's 1100 Words You Need Know