Traitor’s Codex
by Jeri Westerson

An ancient and mysterious book leads Crispin Guest into a deadly maze in this latest medieval noir mystery.

1394, London. Crispin Guest, Tracker of London, is enjoying his ale in the Boar’s Tusk tavern – until a stranger leaves a mysterious wrapped bundle on his table, telling him, “You’ll know what to do.” Inside is an ancient leather-bound book written in an unrecognizable language. Accompanied by his apprentice, Jack Tucker, Crispin takes the unknown codex to a hidden rabbi, where they make a shocking discovery: it is the Gospel of Judas from the Holy Land, and its contents challenge the very doctrine of Christianity itself.

Crispin is soon drawn into a deadly maze involving murder, living saints, and lethal henchmen. Why was he given the blasphemous book, and what should he do with it? A series of horrific events confirm his fears that there are powerful men who want it – and who will stop at nothing to see it destroyed.


Lively … Brisk prose and well-drawn characters propel this nimble excursion into religious thriller territory

Publishers Weekly

Grim, gritty, and utterly enthralling, Westerson's gripping narrative pulls the reader deep into the dark underbelly of the Middle Ages


Typical of the series, the story is well plotted and comes with a deeply satisfying resolution. Another winner

Booklist on The Deepest Grave

Series fans will be on familiar ground, and, because the author makes sure to provide some background on Crispin Guest, newcomers can jump right in

Booklist on Season of Blood

Jeri Westerson

Jeri Westerson was born and raised in Los Angeles. As well as nine previous Crispin Guest medieval mysteries, she is the author of a paranormal urban fantasy series and several historical novels. Her books have been nominated for the Shamus, the Macavity and the Agatha awards.

View author page


Traitor’s Codex by Jeri Westerson is available in the following formats

Hardback97807278887543rd June 2019145 X 223mm208$28.99
Hardback978072788875428th February 2019145 X 223mm208£20.99
Hardback - Large Print978072789230029th November 2019143 X 223mm288$36.95
Hardback - Large Print978072789230030th September 2019143 X 223mm288£22.99
Paperback97818475198702nd March 2020138 X 216mm224$17.95
Paperback978184751987031st December 2019138 X 216mm224£12.99
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