The book has 5 legitimate ACT tests, with fully explained answers to each test.
My junior year I took the ACT with the rest of my class, and got composite: 25, English: 25, Math: 28, Reading: 26, Science: 19
My senior year I took the ACT again midyear, studying the Real ACT a month prior to the test, and got Composite: 28, English: 33, Math: 32, Reading: 25, Science: 22.
Similar to many others, I hate standardized tests. But, a big way to prepare for them is by taking the right classes senior year. My senior year included an English 101 writing course, and pre-calculus. Both classes greatly helped me improve in their respective studies.
If you want to improve your reading score, this book will NOT help you. Reading for speed is something you build with practice, and reading for different elements of literature is something you build by taking a moment to reflect on text you read. I did not read much during my senior year, so I must admit the ACT score accurately reflects that.
Unfortunately, I have no advice for Science. You can love physics, or admire chemistry and biology if not all three, but that does not mean anything on the ACT Science test.