On the Pakistani side, the road was constructed by FWO (Frontier Works Organisation), employing the Pakistan Army Corps of Engineers. The Engineer-in-Chief's Branch of the Pakistani Army completed a project documenting the history of the highway. The book History of Karakoram Highway was written by Brigadier (Retired) Muhammad Mumtaz Khalid in two volumes. In the first volume the author discusses the land and the people, the pre-historic communication system in the Northern Areas, the need for an all-weather road link with Gilgit, and the construction of Indus Valley Road. The second volume records events leading to the conversion of the Indus Valley Road to the Karakoram Highway, the difficulties in its construction, and the role of Pakistan Army Corps of Engineers and their Chinese counterparts in its construction.