The End of Reason is a short book that is mainly a critique of Sam Harris' two books, The End of Faith and Letter to a Christian Nation. If your interested in a more developed apologetic of general atheism, I would suggest Ravi Zacharias' other book, The Real Face of Atheism.

In The End of Reason, Ravi Zacharias rebuts Sam Harris' happy atheism and his depiction of theism as a backward and dangerous belief system. Harris seems to forget that the 20th century was the bloodiest century in human history where the main players were atheists. For example, Mao Zedong was motivated by his scientific atheism. He bragged, "They are theists and we are atheists" (Mao Tsetung, Selected Readings from the Works of Mao Tsetung, Foreign Languages Press, Peking, China, 1971, p. 482). Stalin was another famous atheists responsible for killing millions. Adolph Hitler was no friend to Christians. For example,

In the Diocese of Chelmno, where about 650 priests were installed before the war, only 3 percent were allowed to stay, the 97 percent of them were imprisoned, executed, or put into concentration camps. .. By January 1941 about 700 priests were killed, 3,000 were in prison or concentration camps. ... The Tribunal will recall, from the previous reading of this document, the imprisonment of 2,800 priests and lay brothers in Dachau alone from 1940 to 1945, of whom all but about 800 were dead by April 1945, including an auxiliary bishop. Trial of The Major War Criminals before The International Military Tribunal, Official Text in the English Language, Proceedings November 14-30, 1945, Nuremberg, Germany, 1947, Vol. IV, p. 518-9. 

The End of Reason is a worthwhile read.