When working through basic knowledge to mastery of a topic, attempting to teach someone else is an extremely effective way to organize your thoughts and learn yourself. This is why graduate students teach undergraduate students.
The author of the original book shouldn't feel shame for making the mistake of working toward mastery of the topic. But racing to publish is dangerous when the topic is as serious as (heart surgery or) cryptography. A stern warning is worth repeating.
Most of us already read the review anyway.