I would rate it 4.5 / 5. The book is concise, but succeeds in delivering essential advice. The author, a well-known Islamic scholar, was influenced by Ahlul-Kalam and Soofiyyah, therefore one must approach his works with this in mind.
The book is a letter the scholar wrote in response to a series of questions posed to him by his student, therefore, it is not a comprehensive book of advice, but rather it addresses that specific student’s concerns. Although, it does answer extremely important points and provides amazing insights which we can all benefit from.
The scholar did not talk about issues of marriage, something which is a huge part of life and of extreme importance in Islam. I would have liked to hear some advice regarding it.
My main take away is that action requires knowledge of the shariah and salvation requires action. Sincerity is of utmost importance and striving against base desires is essential.