The September 13, 2009 edition of The Denver Post features a review of Selene Castrovilla's Upon Secrecy:
"Paging students and teachers studying the American Revolution: Here's a lively, obscure story that will make you sit up. Castrovilla's slim book about the Culper spy ring may look like a picture book, but the text would be a great supplement for high school history classes… The research behind both text and illustrations is impeccable."
