Redhead by the Side of the Road - Anne Tyler, Vintage Publishing

Micah Mortimer isn't the most polished person you'll ever meet. His numerous sisters and in-laws regard him oddly but very fondly. He measures out his days running errands for work, maintaining an impeccable cleaning regime and going for runs (7:15, every morning). He is content with the steady balance of his life. But then the order of things starts to tilt. And when a teenager shows up at Micah's door claiming to be his son, Micah is confronted with another surprise he seems poorly equipped to handle...