This text provides a comprehensive and concise guide to all the medieval English castles of which something can still be seen today. A short introduction supplies the historical background of the great explosion of castle building in the Middle Ages, and there is a glossary covering all aspects of castles in some detail. A guide to over 600 castles in England. It gives a fair amount more detail than Fry's Castles of the British Isles and lists a few more sites and includes town walls. Definitely the next step up from Fry'
Castles of the British Isles but not as comprehensive as Salter's specific county gazetteers, or D J C King's classic
Castellarium Anglicanum in that Pettifer generally ignores lost sites. However, for those who want a glove box guide to all England's castles "worth visiting" with rather more content than Fry's this is the book.