I read this charming story in a couple of days and enjoyed it for what it is. It's a fluffy and sweet romantic fantasy which is a fun summer read, with one caveat which will determine your enjoyment, your willingness to suspend your disbelief. Let me explain.
The book centers around Jane Margaux, the daughter of successful Broadway producer, Vivienne Margaux. At the story's onset, Jane is a sad and lonely 8 year old about to turn 9 whose only source of love and companionship come from her imaginary best friend, Michael, a gorgeous, funny and caring man that only she can see. Unfortunately, as luck would have it, on Jane's 9th birthday Michael informs her that the rules for imaginary friends dictate that he must leave her and go to another case, to help another child who needs him. Jane is heartbroken and though Michael tells her that she'll forget him since that is the natural course for all imaginary friends, Jane assures him that she'll never forget him. And she never does. Years later, Jane is a successful playwright on the cusp of bringing her hit play "Thank Heaven" to the movies, she's dating an actor from her play, and working for her mother, but she's still lonely and full of doubts and uncertainties. Then one day after a huge fight with her boyfriend, she's back sitting alone at the St. Regis, a favorite spot of Michael and hers, eating her favorite dessert when she looks across the room and has to blink twice to clear her eyes, because sitting there is none other than...Michael.
The book's jacket states "What if your imaginary friend from childhood was your one true love?", and the story is an answer to that question. This is not one of Patterson's typical suspense novels, it's more in the vein of "Suzanne's Diary for Nicholas" though "Sundays at Tiffany's" doesn't quite measure up to that standard. I'll reiterate that your enjoyment of this book will totally depend on your willingness to suspend your disbelief and just enjoy the story as a sweet romantic fable. If you can do that, than you might enjoy this light and quick read.