Jackaby is a supernatural twist on Sherlock Holmes for YA readers. The whirlwind action surrounding the killings takes on an almost realistic tone when told for the view of Abigail Rook. Newly to the US, she becomes Jackaby's assistant (not really by his choice) and we get the unique perception of someone who is being influenced by the supernatural world, yet is blind to it. Jackaby CAN see and interact with it, causing much confusion to the people around him. This is great for the story and character development. 
 Abigail Rook is a 'normal' girl with no gifts other than being normal. Something Jackaby seems intrigued by. She is the character with the most development; going from a skeptic to a believer and willing to place her life in Jackaby's hands. Even saying this, she's not a gullible/complete believer. Proof is still needed in someway or another. 
 R. F. Jackaby is the main detective. He is a seer, someone who can see the supernatural world. While compared even by Abigail to Sherlock Holmes, he is not as great of a mind, nor does he notice as much mundane things. But he is good at what he does, even if at times he forgets to take into consideration others around him. 
 The supporting characters come in all shapes, sizes, and species. They help to create the scenery and push Abigail into becoming the strong character she is at the end. While the book is titled Jackaby, it is more about Abigail and how her association with Jackaby changes from the student who ran to the states to avoid facing her parents to the woman she is at the end. 
 I think the culprit was fair obvious, but that in no way took away from my enjoyment of this book. I HIGHLY recommend this book to mystery lovers who don't mind a the dash of fairy for added spice. 5 Stars.