This work is hampered by much pseudo-information in books and on internet that is at least imaginative and at worst sensational. Such work is often characterized by repetition of earlier published information without presenting any or sufficient primary sources. Obviously, well documented information, based on sound historical research with ample professional references, preferably primary sources, is of the utmost importance for an objective picture of the Knights Templar, their origin and their impact then and, probably, now.
The following set of well annotated sources are sound and valuable introductions to professional literature on the Knights Templar. A useful collection of annotated primary sources is The Templars Selected Sources Translated And Annotated by Malcolm Barber and Keith Bate (2002).
The best introductions to the Templars are
* Malcolm Barber, The New Knighthood: A History of the Order of the Temple (1994, reissued 1996)
* Alan Forey, The Military Orders from the Twelfth to the Early Fourteenth Centuries (New Studies in Medieval History) (1992)
* Helen Nicholson, The Knights Templar: A New History, new ed. (2004).
Malcolm Barber, The Trial of the Templars, 2nd ed. (2012).
Templar myths are the subject of Peter Partner, The Knights Templar and Their Myth, rev. ed. (1990).
A full collection of books thought of by scolars as sound and reliable can be found on our special "Reliable Books" Page.