There are 4 books in the Doc and Tweed History Mysteries series.
The Doc and Tweed History Mysteries series does not have a new book coming out soon. The latest book, The Benedict Arnold Cipher (Book 4), was published in January 2006.
The first book in the Doc and Tweed History Mysteries series, Peril at Pig's Eye Cave, was published in January 2004.
The Doc and Tweed History Mysteries series primarily falls into the Mystery genre. This middle grade series was written for ages 8-12, but can be enjoyed by older readers as well.