The folowing is adapted from Ordnance Survey maps: a concise guide for historians (third edition) by Dr. Richard Oliver. 

Dr. Oliver comments : The only popular history of the Ordnance Survey is Owen and Pilbeam (1992). Its principal defect is that it has been out of print for some time: it is the sort of book which needs to be either revised or reissued, or else suitably replaced, every five or seven years or so. Seymour (1980) is a much fuller account, but the sections dealing with events in Britain in the period 1825-70 are defective, as will be seen by comparison with my doctoral thesis (Oliver (1986)). 

Short History of Ordnance Survey of Great Britain, by Dr. Richard Oliver