The author, Tim Challies, is a popular Christian blogger. He is gifted in writing, and his theology is well-informed and reformed. He tackles the topic of spiritual discernment systematically, and I found it helpful. It also shows that his wide reading, which helps the content of the book interesting and engaging.
Strangely enough, however, the last chapter, where the author delves into very practical steps of spiritual discernment, was the biggest dissappointment. I wouldn't say that I didn't learn anything from that chapter, I think there were some helpful things to learn from his steps/list to discernment. But having a list of steps, in a particular order, felt too rigid and pragmatic for me to digest. Tim Challies himself acknowledges that the steps will come more naturally as you grow in discernment, and the order will not be always kept the same. I think it is to be taken as a helpful starting point as you learn to discipline your own way of thinking, but not as a rule to be followed all the time. I think that's what the author intended anyway.
All in all, it was an easy to read, helpful, and persuasive book, in which a Christian brother calls for spiritual discernment with love and conviction. I would recommend this book to young and mature Christians.
[You can buy this book from Koorong or Amazon among many places.]