Promoted as part of the Modernisation Plan of 1955, the electrification at 25kV of the West Coast main line from London to Birmingham, Manchester, Liverpool and ultimately Glasgow was one of the most ambitious schemes to emerge from the Plan. Although there had been electrification of main lines before, such as the short-lived line from Newport to Shildon and the LNER proposals for the Manchester-Sheffield line via Woodhead, these routes had been selected primarily for freight purposes; the WCML plan envisaged the conversion, to the most modern standards, of one of the core main lines in the country. The conversion was to establish the standard for future work on the ECML and the GER route to Norwich. Work started in the late 1950s and, although the first stretch was energized in 1960s, it was not formally opened until June 1961. Gavin Morrison provides a record of the various types of 25kV AC locomotive constructed over the past half century. Some of these classes are now as much a part of history as the steam locomotives that they were destined to replace, whilst others remain at the forefront of main-line service. The book also includes a historical examination of the development of electric locomotives, allied to the colour illustrations with detailed captions.