Featured on PDR in the collection Self-Portrait by Ernst Mach (1886)

This unique self-portrait, also known as "view from the left eye", is the creation of Austrian physicist and philosopher Ernst Mach, noted for his contributions to physics such as the Mach number (which relates an object's speed to the speed of sound) and the study of shock waves. The sketch appears in Mach's The Analysis of Sensations, first published in German in 1886 as Beiträge zur Analyse der Empfindungen, and is used to illustrate his ideas about self-perception.