It was amazing. The whole series is amazing. I've read several books now where the hero has some form of Aspergers. This was by far the most well done. Ian's difficulties are real, but he is not a caricature. Beth's devotion to him is realistic also. Yes, she has her own problems but it never seems like she's with him as a last resort or in a caretaking role. 
 The set-up for other books in the series is light though I did feel some of the scenes in the mistress's house are over done. But those criticisms belong to another book.