There is no doubt that Greg Bahnsen not only fully understood Van Til's apologetic, he attempted to fully apply it to every area of life. This book is his best and most cogent work. Bahnsen, better than anyone else, was able to communicate Van Til's system and help others to understand it and use it. I recommend getting his taped debates with Atheist Gordon Stein (now deceased), and Atheist Edward Tabash, in order to hear how the system is applied. Michael Martin and others have tried to develop an answer to Bahnsen's fine tuning of Van Til's system (the TA - Transendental Argument), but so far their efforts have proved pitifully futile.
Other reviewers have done a good job of laying out the format of the book, so I will not repeat it here. I just wanted to include a few words of recommendation for this tremendous and timeless work by one of God's servants who is greatly missed.