From the author of The Bride Test comes a romance novel hailed as one of The Washington Post's 50 Notable Works of Fiction in 2018 and one of Amazon's Top 100 Books of 2018! "This is such a fun read and it's also quite original and sexy and sensitive."--Roxane Gay, New York Times bestselling author "Hoang's writing bursts from the page."--Buzzfeed A heartwarming and refreshing debut novel that proves one thing: there's not enough data in the world to predict what will make your heart tick. Stella Lane thinks math is the only thing that unites the universe. She comes up with algorithms to predict customer purchases--a job that has given her more money than she knows what to do with, and way less experience in the dating department than the average thirty-year-old. It doesn't help that Stella has Asperger's and French kissing reminds her of a shark getting its teeth cleaned by pilot fish. Her conclusion: she needs lots of practice--with a professional. Which is why she hires escort Michael Phan. The Vietnamese and Swedish stunner can't afford to turn down Stella's offer, and agrees to help her check off all the boxes on her lesson plan--from foreplay to more-than-missionary position... Before long, Stella not only learns to appreciate his kisses, but crave all of the other things he's making her feel. Their no-nonsense partnership starts making a strange kind of sense. And the pattern that emerges will convince Stella that love is the best kind of logic...