I think one book for the list would be
A Dress for Diana by the Emmanuels. It's a sweet snapshot of those months leading up to the wedding. I enjoyed seeing the behind the scenes photos of making the dress but as one of my interests is in costuming I am biased. It's the first time I'd seen a detailed photo of the shoes and I was amazed at the handwork for those. The finishing details that weren't seen onscreen but are in the photos here are fabulous. I confess I haven't read up on all the latest gossipy books but I usually prefer a straight biography to tell-all books in general. I did read the Andrew Morton book when it first came out years ago. I enjoyed it but still remember to consider the source on all such stories with a huge grain of salt.