I think the real problem with biographies of lesser known women in history, is that there just isn't enough known information out there about them to make their biographies interesting. Women's lives just weren't recorded in any detail so there is often no "paper trail" to follow and we just don't know what they thought or even where they were at any given time, so a biography like this one comes pretty much down to speculation from very little hard evidence or the author has to admit that we just don't know. Neither really makes for riveting reading.
While Mary Boleyn lived in interesting times and belonged to a family which was at the heart of politics at the time, she herself seems to have made very little impact. There are two extant letters, some legal paperwork to do with an annuity and her inheritance, and a whole raft of rumours. Not much for any biographer to go on, and Weir struggled to make much of it.
The good bits though, were the fact that Weir did seem to do thorough research and did turn up some interesting facts about Henry VIII and the Boleyn family that I was unaware of. And although she didn't "explode the mythology" or "present compelling new evidence" as claimed by the jacket blurb, she did reach some credible conclusions regarding Mary's life. It is not to say however, that I agreed with all the conclusions she came to in regards to Mary, as a lot of the stuff just can't be proved either way (there is really just not enough evidence or information) and it mostly comes down to an educated guess.
It was nice to see Weir take a more even handed approach in this biography as a common complaint about her work is bias, but in doing so she seemed to loose something because despite what others have said about her historical accuracy, I have always found her biographies very readable and at times, page turners. This one however felt like it was missing something, and I fear her efforts to be taken seriously as an historian has been detrimental to her writing style.
On the whole though, this biography was an enjoyable read and probably the most comprehensive book on Mary Boleyn available at this time.