The Girl He Used to Know by Tracey Garvis Graves

Ten years after they first meet in college, Annika and Jonathan bump into each other at a grocery store in Chicago. Annika has her dream job working as a librarian, while Jonathan has a high-powered job in finance. It's obvious that they still have feelings for each other and that there are things from the past that were left unsaid. The Girl He Used to Know recounts both the development of their relationship in the early 1990's, when Annika was a shy, awkward, yet beautiful young woman with undiagnosed autism-spectrum disorder (whom Jonathan fell for because she was so unique and refreshing) and their reunion ten years hence. It's a moving portrayal of what everyday life is like for someone on the spectrum as they move into adulthood and become independent and find love.