The book covers the topic of experimental instrumentation at the turn of the 20th century. The authors introduce the role of instruments in the process of establishing psychology as a science. They concentrate on identifying historical devices and problems with rediscovering their functionality. The core of the book consists of a categorized list of instruments with a description of their purpose and mechanical design. The categorization covers recording and time measuring devices, instruments designated for the research of human senses, memory and learning, and devices for physiological measurement. The publication also includes a companion website with short videos demonstrating selected instruments in action.