The pamphlet describes in detail what the 'Geoid' is. Preparation of this pamphlet was prompted by the frequent questions administrators and non - geodists, which centered on that mysterious word " geoid " and is published in the interest of training students at the Defense Mapping School.Smaller than A4 size pamphlet (actually it's more a booklet) of 20 pages. The last two pages are not numbered and blankroyal australian survey corps, defense mapping school fort belvoir, virginia