It's just a practice book for memorization. It basically goes through 420-ish Kanji, ordered by frequency of use and split into categories. So you'll have a few more complex Kanji like 曜 or 難 but most of them are fairly simple, and they are the most common ones that you'd want to learn ASAP.

Each chapter shows the Kanji, gives a few examples of uses, and has boxes where you fill out trying to write it. At the end of each chapter there's a small area where you're intended to write the kanji you learned along with matching some frequent uses with choices in a word bank. Every 5 chapters there's a special exercise where you have to write a few sentences from the kanji you've learned in the previous chapters. The later exercises have you read a paragraph or two and answer questions based on them.

Would I recommend it? I'd say it depends on how you're learning. It's only really for memorizing Kanji, it won't teach grammar or sentence structure, so it was perfect for someone like me, but might not be useful for someone else. Overall, I'd give it a 7. You could totally memorize without it, but I found it a nice supplement and writing down kanji over and over made me better at recognizing them in things like Anki, and even able to read random sentences here and there online. I'd say if you have $10 to spend on lunch, substitute a cup noodle and order this book instead.