I bought this book after my visit to the castle and I love it. It's an Amazing souvenir and is probably the most complete guide you can get of this place that covers every room, the garden and so much more. It also has beautiful pictures.
Maybe it deserves a 5 star review but I did find the writing a bit dull (ofcourse it's hard to make an entertaining book of this subject). For me it's more of a research book where you'll find all the information you need on the castle but it fails to keep me interested throughout the book.
I still wholeheartedly recommend this book as it's an amazing memory to my visit and perfectly fulfills it's promise of being a guide to this place.