Americanah by Chmamanda Neozi Adichie

Ifemelu and Obinze are young and in love when they depart military-ruled Nigeria for the West. Beautiful, self-assured Ifemelu heads for America, where despite her academic success, she is forced to grapple with what it means to be Black for the first time. Quiet, thoughtful Obinze had hoped to join her, but with post-9/11 America closed to him, he instead plunges into a dangerous, undocumented life in London.