Eleanor Oliphant Is Completely Fine: Reese's Book Club (A Novel) by Gail Honeyman

Meet Eleanor Oliphant: She struggles with appropriate social skills and tends to say exactly what she’s thinking. Nothing is missing in her carefully timetabled life of avoiding social interactions, where weekends are punctuated by frozen pizza, vodka, and phone chats with Mummy. 

But everything changes when Eleanor meets Raymond, the bumbling and deeply unhygienic IT guy from her office. When she and Raymond together save Sammy, an elderly gentleman who has fallen on the sidewalk, the three become the kinds of friends who rescue one another from the lives of isolation they have each been living. And it is Raymond’s big heart that will ultimately help Eleanor find the way to repair her own profoundly damaged one.