It's a good book. Offers pronounciation, definitions, synonyms, and antonyms, as well as good practice. Chances are there are at least some words you'll learn from the book, even if you do well on the diagnostic test but I still suggest that you take that test to see if you should get a higher level book.

Advance vital reading comprehension skills through a balance of appealing nonfiction and fiction titles, focus on strategies and skills critical for reading comprehension, and nonfiction features such as indexes, glossaries, tables of contents, and captions.

Provide explicit instruction and practice of the comprehension skills students need to understand written text. Each lesson begins with direct instruction of each skill and is followed by opportunities for students to apply and transfer the skill to a meaningful context. Comprehension Plus study skills, vocabulary, phonics/word study, and writing connections add up to improved test scores and classroom performance. Comprehension Plus is a perfect combination with Comprehension Power Readers.