For millions of Americans, the holiday season includes a tradition that starts after Christmas – Kwanzaa, the week-long celebration of African-American culture and history. Author and culinary historian Dr. Jessica B. Harris traces the history of Kwanzaa, its community rituals and the foods of the diaspora in her book, “A Kwanzaa Keepsake and Cookbook: Celebrating the Holiday with Family, Community, and Tradition.” It’s our December selection for Bookmarked: The “Under the Radar” Book Club.