Series: Young and Yang (Middle Grade Fic)

AUTHOR: Kristen Kittscher (US)
PUBLISHED: HarperCollins ; 2013.
PAGES/ILL: ~370 pages.
SERIES: Young and Yang. The Wig in the Window ; The Tiara on the Terrace.

PLOT: (Book 1: The Wig in the Window)
Best friends, 7th graders Sophie Young and Grace Yang, love mysteries and have made a game out of spying on their neighbours. When they discover a bloody scene at the home of their bizarre middle-school counsellor, they are on the case to prove she is not what she seems. Soon the girls are breaking secret codes, being followed by a strange blue car, and tailing strangers. As the case heats up, they are under pressure, which threatens their friendship.

REVIEW:
This is a really fun story for fans of The Secret Seven, The Famous Five, Encyclopaedia Brown, and Nancy Drew (and their parents would have likely liked Trixie Belden and the Hardy Boys). The age-range would target children who have long since moved on from the Nancy Drew and the Clue Crew series, but are not be ready for the full series featuring the older Nancy Drew.
The plot has little twists and more suspense than your average middle-grade mystery fiction.
Overall, I highly recommend this series. It would be an appropriate class read-aloud for Grades 4-6

For promoting it in school libraries, I would display this book (along with the others I've listed) together with articles about real-life child investigators, such as this one.

For more mystery and suspense books, check out the list from A Mighty Girl.

AGE: 9+.
GENRE: Detective and Mystery Fiction.
RATING: 4 1/2 - 5 stars.

Series: Phyllis Wong Mysteries (Middle Grade Fic)

AUTHOR: Geoffrey McSkimming (US)
PUBLISHED: Allen & Unwin ; 2014.
PAGES/ILL: ~390 pages.
SERIES: Phyllis Wong Mysteries. Phyllis Wong and the Forgotten Secrets of Mr Okyto ; Phyllis Wong and the Return of the Conjuror ; Phyllis Wong and the Waking of the Wizard.

PLOT: (Book 2: Phyllis Wong and the Return of the Conjuror)
Phyllis Wong, the girl magician, returns to solve a crime from history. Someone has been selling mint-condition copies of Shakespeare's collected plays and Phyllis suspects someone is up to no good. With a secret from her great-grandfather, and with help from her friends Clement and Chief Inspector Inglis, it's up to Phyllis to solve the puzzle and prevent the theft of Shakespeare's missing play.

REVIEW:
This is a fun story, and although I won't go out of my way to read another in the series for my personal choice, I can see it being popular with middle-grade girls. I would have no problem recommending it to children who like 'Matilda' by Roald Dahl.
The book series also has a web-site.

AGE: 9+.
GENRE: Realistic fantasy.
RATING: 3 1/2 stars.

Series: Ace Detectives (Kids Inc series) (Jnr Fic)

AUTHOR: Geoff Patton (AUST) (2007)

PLOT: A group of teenagers join together to create a detective agency, solving crimes in their town.
NOTES: A 4-book series. Well-written. Children will enjoy following the clues along with the characters. Part of the Kids Inc series'.
Good follow-up books would be Encyclopaedia Brown, etc.

AGES: 7-10.
GENRE: Realistic Fiction, Adventure.
RATING: 4 - 4 1/2 stars.