Thierry Meyssan (French pronunciation: ?[tj??i m??s??]; born 18 May 1957) is a French journalist and political activist.He is the author of investigations into the extreme right-wing (particularly about the National Front Militias, which are the object of a parliamentary investigation and caused a separation of the extreme right-wing party), as well as into the Catholic Church (Opus Dei, for example).Meyssan's book 9/11: The Big Lie (L'Effroyable imposture) challenges the official account of events of the September 11 terrorist attacks.