The three essential books of Francis Schaeffer in one volume:
The God Who Is There
Escape from Reason
He Is There and He is Not Silent
 
"There is no other important Christian thinker of our era who has tackled as many fundamental intellectual, philosophical, and theological issues as Schaeffer did, and no one else has so revealed their relevance to us." ( Dr. Harold O.J. Brown, Trinity Evangelical Divinity School)