If I had written this review a week ago when I read the book, I believe my review would have been different from what is to follow. My first impression was a mix of love and like. Not bad, right? Seven days later...I loved this book. I've made no secret as to my feelings of Izzy's actions, and frankly, my feelings on her sleeping with Celyn haven't changed a bit. There were issues not addressed in regards to Izzy sleeping with Celyn for the reader, but I had the advantage of re-reading the series shortly before reading this installment and if this book had contained tantrums and blow-ups or even concern about Celyn in the picture then I think as the reader I wouldn't have been convinced either Izzy or Eibhear had matured enough to get to this point. I know I can't have it both ways, so I'm pleased the romance was between two mature adults--although Izzy had her moments making her, still, one of my least favorite characters. What I do appreciate is Eibhear maturing enough to have apologized to Izzy for his actions and no groveling being involved.Overall, I found Izzy and Eibhear's coming together appropriate and quite enjoyable for the persons they have become and not the characters they were 10 years prior.What really made this a 5-star book for me was the overall story. Aiken's books have evolved into a series that not only has strong characters, but a strong plot to support those characters. Because Izzy and Eibhear's book has been so built-up many series would have difficulty following such a book. "How to Drive..." has only notched up my desire for more. More characters and more story. The twins, Rhi, Brannie, Aiden, Frederick...the more the merrier. I can't seem to get enough of this series.Sidenote: What I missed in this book has no bearing on my enjoyment, but two lingering questions from the previous books.1. Did Ragnar Claim Keita?2. Has Brastias aged 10 years or did he get the Chain of Beathag as well. If I missed the answers to these questions, please would someone let me know, because I can't stop wondering.Pre-release statement:I know I will end up giving this book 5-stars. I love the series but mostly the author. I have to admit I' ve been irritated with Izzy for sleeping with Eihbar's cousin. I don't think she should have waited around for Eihbar, but his cousin...really? While I'm supposed to believe she loved him too. I think Aiken gave her a pass in book 5 and it has bothered me since. I' m looking forward to the series beyond this book because I think Izzy should have to work for Eihbar, not the other way around. Knowing this won't happen will not prevent me from reading the book or enjoying it. Needed to vent that, it's been bothering me.