My first wish granted on NetGalley! Thank you so much for this ARC! 
The first book I read by Sarah Adams was When in Rome which I thoroughly enjoyed so when I saw her new 2024 release, The Rule Book, I thought I should read the companion novel first, The Cheat Sheet, which was published in 2021. Unfortunately I didn't overall enjoy The Cheat Sheet but I still wanted to try out The Rule Book, being a newer release. There are cameos from the characters of The Cheat Sheet, Nathan and "Bree Cheese", so if you enjoyed this couple more than I did I'm sure you'll like this aspect of the book. 
If you love tropes in romance, The Rule Book is full of them! There is "one bed", "fake marriage", "second chance romance", etc. and these all worked for me, especially the "fake marriage" which I loved. I also loved the career discussion, both Derek's and Nora's, and the representation of dyslexia in the narrative.
However, I just don't know why this book didn't keep my attention, it took me so long to get through and I just wasn't into this book as much as I hoped. I really see an improvement in Sarah Adams' writing since The Cheat Sheet but it didn't quite live up to When in Rome for me.
Also worth noting is that The Rule Book is more "open door" when it comes to sexual/explicit scenes than previous books by this author, something which is addressed in the Author's Note & Content Warning at the beginning of the book. Chapter 34 is where you'll want to skip if you want to keep the reading experience "closed door".
3 stars

Thank you to NetGalley, Headline and Sarah Adams for the opportunity to read this advanced reader copy.