In the first book, The God Who Is There, Schaeffer shows how modern thought has abandoned the idea of truth with tragic consequences in every area of culture--from philosophy, to art, to music, to theology, and within culture as a whole.
Escape from Reason, the second book, explains especially how the disintegration of modern life and culture grows from corrupted roots that reach far into the past.
In the last book, He Is There and He Is Not Silent, Schaeffer contrasts the silence and despair of modern life with the Christian answer that God can indeed be known because He is there and He is not silent. In addition to the convenience of having Schaeffer's three foundational books in one volume, the Trilogy is especially valuable in that it uses the text revised and updated by Schaeffer shortly before his death.