Ficre Ghebreyesus and Elizabeth Alexander were born two months apart in 1962, he in Eritrea, she in Harlem. They didn’t meet until 1996. He was an artist and a chef at a New Haven Eritrean restaurant he owned with his brothers. She was a poet and professor. She had been teaching at the University of Chicago, where she had also met a senior lecturer named Barack Obama. She married Ghebreyesus. She delivered Obama’s 2009 inaugural poem. In 2012, a few days after her husband’s 50th birthday, he died abruptly. Her new book, “The Light of The World,” tells that story.