Direct laryngoscopy, a signature skill of the modern anesthesiologist, can be daunting to learn and difficult to teach. Before the advent of video laryngoscopy, the Dual-Vu Scope (left) cleverly applied the physics of a periscope. First designed in 1854 by French inventor Edme Hippolyte Marié-Davy, the periscope consisted of a vertical tube with a mirror at each end. Parallel to each other but at 45 degrees to the tube’s axis, the mirrors reflected rays of light, revealing what friend or foe might lie on the other side. During World War I, the battlefield periscope shielded soldiers in the trenches by providing indirect visualization of enemy lines (right). Similarly, past anesthesiology residents could peer down barrels of Dual-Vus while instructors safely directed their views to laryngeal targets. Whether in the trenches of the battlefield or residency training, periscope mechanics enhanced tactical vision. (Copyright © the American Society of Anesthesiologists’ Wood Library-Museum of Anesthesiology.)