The first book in this series, Hope Defined: A Postmillennial Primer, was a concise introduction to optimistic eschatology. How you view the future significantly impacts how you live today, which is a major reason for the publication of this trilogy on postmillenialism.
While the first book focused on the postmillennial position itself, this current volume focuses on our relationship to Christ's victorious reign - the roles we play and how they affect the present manifestation of the kingdom. Some might consider this an apologetic tool for our active efforts to extend God's kingdom, and they would be right.
Postmillennialism isn't for doctrinal musing alone, it informs and empowers our walk in Christ's victory over sin, death, and the devil.