Silhouettes were a hugely popular and democratic form of portraiture in the 19th century. So an old ledger book full of cut paper profiles at the National Portrait Gallery caught a conservator’s eye. It promised a rare glimpse at people from all different backgrounds who lived in early America. It also held a surprise: It was laced with poison.

Lizzie Peabody, host of the Smithsonian’s Sidedoor podcast, brings us the story of the book, the man who created it, and the web of overlapping stories tucked inside.

See William Bache’s book of silhouettes here.