Geocentric model knew about Tusi's work or that of the Maragha school. Not all Greeks agreed with the geocentric model. The Pythagorean system has already been mentioned; some Pythagoreans believed the Earth to be one of several planets going around a central fire. Hicetas and Ecphantus, two Pythagoreans of the 5th century BC, and Heraclides Ponticus in the 4th century BC, believed that the Earth rotated on its axis but remained at the center of the universe. Such a system still qualifies as geocentric. It was revived in the Middle Ages by Jean Buridan. Heraclides Ponticus was once thought to have proposed
Encyclopedia of the Central Intelligence Agency if he would instead be interested in writing an encyclopedia detailing the history of the CIA. Smith agreed as he felt the CIA was highly relevant to military history. "Encyclopedia of the Central Intelligence Agency" was first published in 2003 by Facts on File. It was released in both hardcover and paperback formats. An eBook edition was published the same year. Additionally an eBook was also published in 2003 in Great Britain. In the "Encyclopedia of the Central Intelligence Agency", Smith discusses and defines key concepts relating to intelligence gathering, including "clandestine mentality", a colloquial term used to characterize what