A guide to 200 of the main castles of Wales. It has a bit to offer over Fry's
Castles of the British Isles in it's concentration on Wales, it's slightly more detailed histories and it's short glossary of Welsh terms. It it is a pleasant and readable book but gives few map references and no bibliography. Like all such books misses most minor sites with no history and can not do justice to major sites. This is a small book that will fit into the glove box but the slightly larger, slightly more expensive,
Welsh Castles by Adrian Pettifer is a much better book.