Although I am not a fan of Nee's taxonomy, the truth that lies beneath the words is pure gold and worth the effort to mine it out. I found myself simply making mental substitutions as I read, e.g. I might change 'soul' to 'self' if I thought it agreed more with Scripture. The core teaching exposes the truth of Scripture about this subject which also happens to reflect my life experience, almost without variation.
I have bought this book several times over the years to give away. It is so powerful and will make you hungry to read and apply everything that Watchman Nee ever wrote. That is because the Holy Spirit will witness directly to your spirit as Scripture is expounded and Jesus is lifted up, and you will understand the process the Lord uses to create true disciples.
The book contains a deep level of understanding about how the Lord deals with His children. We desperately need preachers and teacher like Watchman Nee in our contemporary Christian church. So few are willing or able to share the deep truth contained in the pages of this book. A "must read" for anyone that truly wants to be used of God.