Forgiveness is often the solution, observes Precious Ramotswe toward the end of Smiths warmhearted, humane 17th No. 1 Ladies Detective Agency novel (after 2015s The Woman Who Walked in Sunshine). Mma Ramotswe is referring to the books main case, which involves a Canadian woman in her late 30s, Susan, who spent her childhood years in Botswana and now wants to find Rosie, the nurse maid largely responsible for raising her. Mma Ramotswe places an ad in a Gaborone newspaper, which brings a woman who claims to be Rosie to the detective agency. Grace Makutsi, the agencys prickly codirector, suspects this Rosie is a fraud, while Mma Ramotswe senses something not quite right about Susans quest. Meanwhile, the ladies deal with a couple of minor cases: their assistant Fanwell rescues a stray dog that needs a home, and Mr. Polepetsi, their sometime helper, becomes an unwitting pawn in a pyramid scheme involving cattle. As ever, Smith adroitly mixes gentle humor with important life lessons. Agent: Robin Straus, Robin Straus Agency. (Nov.)