 Tobias later recanted and distanced himself unequivocally from the Intelligent Design parts of the book in a letter published in "Die Burger".Claassen is the author or co-author of 14 books, including "Geloof, Bygeloof en Ander Wensdenkery – Perspektiewe oor Ontdekkings en Irrasionaliteite" (Faith, Superstition and Other Wishful Thinking – Perspectives on Discoveries and Irrationalities) that was published by Protea Boekhuis in July 2007 and in February 2008 went into a second printing.In 2014, his book on quackery, "Kwakke, Kwinte & Kwale