This book is a fine introduction to castles. Seventeen illustrated thematic chapters give a solid base to the understanding of castles and the gazetteer of more than a thousand of the best castles of the British Isles is one of the most comprehensive that is readily available. Well written and illustrated throughout it is essential grounding for the castle buff.
Available in various editions with somewhat different names but basically the same content. The latest edition is called Castles: England, Scotland, Wales, Ireland and was published in October 2005 and has been completely revised and redesigned).
449 sites in England.
188 sites in Wales.