This is a very short book which is a fictional account of the thoughts of the six wives of Henry VIII at the end of their time as his wife (or in Katherine of Aragon's case, when she died). From the title and the blurb I expected this to be in the form of letters written to Henry, but it didn't seem to work like that, and in fact there seemed to be very little actually to do with Henry in some of them.
The portrayal of Katherine Howard didn't really go down well with me, it just doesn't seem in character, and barely even considers Thomas Culpepper, never mind her last words about rather having been his wife.
In fact, none of the portrayals really struck me as particularly good, Katherine was predictably stuck in her views til the end, but not with the passion that I have seen in other books from 'her' point of view, Anne Boleyn didn't seem particularly witty or smart and Catherine Parr just came across as bitter, rather than caring as other books portray her. The only wife I even treacly believed part of was Anne of Cleves, and her joy at the annulment of her marriage.
I'd say as a quick read it is good, but if you're looking for something to really immerse yourself in Tudor England then this is not the book for you.