By Pullman, Philip  In nineteenth-century London, sixteen-year-old Sally Lockhart, a recent orphan, becomes involved in a deadly search for a mysterious ruby. Sequels: The Tiger in The Well, The Shadow in the North

By Plum-Ucci, Carol 

Torey Adams, a high school junior with a seemingly perfect life, struggles with doubts and questions surrounding the mysterious disappearance of the class outcast.

By Colfer, Eoin  Twelve-year-old private investigator Fletcher Moon, nicknamed "Half Moon" because of his shortness, must track down a conspiracy or be framed for a crime he did not commit.

By Brockmeier, Kevin  After a seventh-grader discovers that the grooves in his Thigpen-brand blue jeans are encoded with a cry for help, he sets out to save the factory workers from greedy entrepreneur Howard Thigpen.

By Abraham, Peter 

Like her idol Sherlock Holmes, eighth grader Ingrid Levin-Hill uses her intellect to solve a murder case in her home town of Echo Falls. Also check out the sequels:

Behind the Curtain and Into the Dark.