Part Real Housewives guilty pleasure and part unravelling mystery, Melissa de la Cruz’s The Birthday Girl is (probably) the first book I have ever categorised as 'a fun thriller'. Maybe that isn’t really a genre, or even a sub-genre, but it is a great way to accurately describe this thoroughly enjoyable, but still suspenseful and twisted tale ... Events from the two timelines ultimately meet up (in a sense), and the story finally brings some of the thriller elements into the present-day timeline, though not as successfully as they were weaved into the past events. The mystery that very successfully unravels in the timeline from twenty-four years ago, did not flow quite as easily into the present-day storyline. There are some very good twists, however, that might have been ruined if the mystery was woven into the two timelines equally ... The story wraps up in a way that felt natural, and true to the characters we had come to know at the party, throughout the evening. It may take an extra minute for the two timelines to match up once the reader has gotten through all the twists and turns, but all the questions do get answered ... This book is a perfect on-the-beach or by-the-pool read, where a 'fun thriller' is preferred over something more complex or intricate.