(Houghton Mifflin Harcourt, 288 pp.) What鈥檚 an 11-year-old Ghanian immigrant to do when he finds a dead body (he knows the victim) in front of his London housing project? Young Harri decides he must investigate, and then proceeds to charm readers with his commentary as he puts into practice the 鈥淐SI鈥-type techniques he鈥檚 seen on TV. (July)