Very long biography -- and unfortunately rather old (it was written just after Princess Grace's death). Still, this is the best of the Grace Kelly biographies I've read and the one I'd recommend to someone who really wants to learn about her, even though it's hard to find today.
I especially appreciated how Englund not only gathers facts and data using a wide range of sources (interviews with friends and family, newspaper articles, archival materials), but also interprets it to help the reader understand why this matters and what it tells us about who she was as a person. For example, he does a nicely nuanced exploration of her complex relationship with her family in the years after her marriage and why that relationship unfolded as it did. Grace emerges as a fully formed human, with both genuine gifts and also very human flaws, not a saint or a nymphomaniac, as some other biographers seem to want to paint her.
The research into the circumstances of her death has expanded in the past decades, so that section seems thin today, but even so he is consistently thoughtful and insightful. I really enjoyed this book.