This brief book contains a series of seven expositions of the churches in Revelation, chapters 2 and 3. As you read through you can't help but gain some idea of the preacher's passion for souls and longing to see Christians walking the way of holiness. These are splendid examples of devotional preaching, with lots of helpful Bible teaching throughout. You get some insights into who the different characters are, such as the Nicolaitans and Jezebel. You also get some historical detail as to what happened to each of the churches as time passed.
My only problem with this book comes during the seventh exposition, on the church at Laodicea. The author has interpreted the passage as a message to unrepentant sinners, who are hesitating and rejecting God's offer of mercy. However, it's worth remembering that the seven letters were written to the actual church. With this in mind, the 'lukewarm' at Laodicea were more likely to have been half-hearted complacent christians, who needed to repent.
Nevertheless, in spite of this, the book still makes for an excellent devotional read. It is a little treasure left for Christians today.