--Erich von Daniken, best-selling author of Twilight of the Gods
"The Ancient Alien Question provides a captivating adventure around the world and sheds an interesting perspective on the Ancient Astronaut Theory. It raises questions that culminate in well-thought-out, and sometimes downright startling, conclusions. A must-read for anyone who wants to expand their knowledge horizon in this kick-ass field."
--Giorgio A. Tsoukalos, author, Gods or Ancient Aliens? producer, Ancient Aliens: The Series
"In The Ancient Alien Question Coppens breaks the intellectual sound barrier and offers his readers a well-researched and well-written book that challenges this last taboo of the human adventure. Definitely a not-to-be-missed book!"
--Robert Bauval, author of The Orion Mystery
"Philip Coppens covers all the bases on this controversial topic. His research is thorough and he addresses each topic with a balanced overview that cuts through the jungle of confusion with a very sharp machete of reason."
--David Hatcher Childress, author of Technology of the Gods