O.W.L.S.: Americanah by Chimamanda Ngozi Adichie

Ifemelu--beautiful, self-assured--left Nigeria 15 years ago, and now studies in Princeton as a Graduate Fellow. Obinze--handsome and kind-hearted--was Ifemelu's teenage love; he'd hoped to join her in America, but post 9/11 America wouldn't let him in.
     Years later, when they reunite in Nigeria, neither is the same person who left home. Obinze is the kind of successful "Big Man" he'd scorned in his youth, and Ifemelu has become an "Americanah"--a different version of her former self, one with a new accent and attitude. As they revisit their shared passion--for their homeland and for each other--they must face the largest challenges of their lives.