See also http://en.wikipedia.org/wiki/Alexander_Thom which opens: Alexander "Sandy" Thom (26 March 1894 – 7 November 1985) was a Scottish engineer most famous for his theory of the Megalithic yard, categorization of stone circles and his studies of Stonehenge and other archaeological sites." Robin Heath recently wrote a book describing Thom's major contribution to the notion of a megalithic science: . Alexander Thom: Cracking the Stone Age Code. Bluestone Press (May 2003). ISBN978-0-9526151-4-9.