It's good to be aware of the pros and cons and make an informed purchase. Pros: - The content of a very long textbook is summarized, focusing only on the key points, making it easy to skim through the material in a short amount of time. - It's good for understanding exam trends and predicting frequently asked questions. Cons: - There are many typos and inaccuracies throughout. It doesn't seem like they update the typos promptly. - It doesn't cover 100% of the content that appears on the exam, so you can't get a perfect score by only studying this. You'll still need to buy and study the textbooks created by the Korean Association of Digital Forensics. Overall: It feels like looking at a college student's notes with important points highlighted. If you have no basic knowledge, it's not a bad idea to buy it and take a look.