For more than sixty years, Harper Lee’s To Kill a Mockingbird has compelled audiences with its astute portrayal of racism and injustice in Depression-era Alabama. In 1970, ten years after the novel was published, playwright Christopher Sergel began working on a stage adaptation that took him twenty years to complete. Sergel’s adaptation is now headed to Berkeley Playhouse, with previews beginning April 28 at the Julia Morgan Theater (2640 College Ave., Berkeley). The play is the first-ever non-musical produced by Berkeley Playhouse, which has focused exclusively on musical productions in the nine years since its founding, and will be directed by Berkeley Playhouse’s producing artistic director, Darren A.C. Carollo. Two sets of young actors ranging in age from nine to fourteen will take on the roles of protagonist Scout Finch, her brother Jem, and their friend Dill Harris, while Steve Rhyne will play Scout and Jem’s father Atticus, a lawyer much-beloved by audiences whom Lee modeled after her own father.