As are all of Sparks books, this one is a masterpiece. It defines the church and the mystery (secret) of God pertaining to the church. It takes you to a different level of understanding altogether. There are Parts one and two of this book and this one is part one. You need to read part 2 also.
As with all of T. Austin-Sparks' books, "The Steward of the Mystery" is a key resource to understanding the more spiritual side of the Christian walk. Well written and very interesting, Sparks leads us on his usual path to knowledge regarding what Christ provides to those who seek Him. If you are looking for greater understanding and praying for enlightenment and revelation, you should add this book to your quest.
I don't understand Christian authors selling their books except to cover the cost of printing. If God gave you the words, then you shouldn't charge others for the Truth. Anyway this book is for free at T. Austin Sparks Website. Also Emmanuel Church will send it to you for free.