I wish I knew what drew Gary D. Schmidt, better known for realistic middle grade fiction such as The Wednesday Wars (a 2008 Newbery Honor book) and Okay for Now (2011), to the story of Martin de Porres, the first black saint in the Americas (actually, Schmidt tells us, Martin was the son of an African mother and a Spanish nobleman, born in Lima and educated by his father in Ecuador). The author's note at the back of Martin de Porres: The Rose in the Desert (illustrated by David Diaz; Clarion, 2012) is no help.
Schmidt's text, however, emphasizes Martin's humility and service to the poor as well as his love of animals (the note does tell us that Martin is patron saint of, among other things, social justice, public education, and animal shelters). And David Diaz illuminates Martin's story with his distinctive mixed-media illustrations, in what the Horn Book calls "Latin American hues [?] of red, turquoise, gold, and brown."
My favorite image is more subdued: It's night. Martin, in his black-and white Dominican habit, carries a basket of bread. He has a brown dog at his heels. Two silvery angels guide his way.