"The Poisoned Pen" is a collection of twelve of Professor Kennedy's adventures. In these, Reeve uses the newest technologies of the early 1900s, which were nothing short of revolutionary for the time. The title story for example features the use of special inks, some appearing and others disappearing in sunlight, making the pursuit of a murderer incredibly difficult for the professor. Each story offers a fascinating look at life in the early 20th century, as well as being loaded with adventure, action, and mystery.