There are 3 books in the The Book Scavenger series series. The newest book is The Alcatraz Escape which came out in 2018.

1
Book Scavenger

Book cover of Book Scavenger
For twelve-year-old Emily, the best thing about moving to San Francisco is that it's the home city of her literary idol: Garrison Griswold, book publisher and creator of the online sensation Book Scavenger (a game where books are hidden in cities all over the country and clues to find them…
When you buy books, we may earn a commission that helps keep our lights on (or join the rebellion as a member).

2
The Unbreakable Code

Book cover of The Unbreakable Code
Mr. Quisling is definitely up to something mysterious, and Emily and James are on high alert. First, there's the coded note he drops at a book event. Then they uncover a trail of encrypted messages in Mark Twain-penned books hidden through Book Scavenger. What's most suspicious is that each hidden…

3
The Alcatraz Escape

Book cover of The Alcatraz Escape
Legendary literary game-maker Garrison Griswold is back in action - this time with "Unlock the Rock," an extravaganza on Alcatraz Island. But just as the fun starts to take off for Emily and James, important items from Griswold's game begin to disappear, and someone is framing Emily's brother Matthew as…