This seminar will bring together a number of scholars to consider collectively the challenges of theorizing, historicizing, and writing about the sonic concept of timbre. Timbre, sometimes called “sound color,” is that quality which tells us that a sound is produced by a trumpet and not an airplane. The American Acoustical Association defines timbre negatively, as the dimension that is different in two musical sounds that are the same in both pitch and loudness. This ingenious definition, which effectively homes in on color and texture of a sound, elegantly bypasses a range of complications that could otherwise arise in the acoustical, psychophysical, and perceptual realm. This negative approach, however, leaves a lot unsaid. Timbre is also closely associated with the sensuous dimension of sound, which has recently emerged as a source of inspiring interdisciplinary work exploring the history of the senses and the experiential dimension of art. In this context, the difficulties of conceptualizing timbre open up the wider field of the arts lodged between the humanities and the sciences—with immediate pedagogical applications. Despite its fundamental nature, groundbreaking work on timbre remains to be done. Especially at a time when the computer-assisted analysis of sounds and their perception has offered a range of new insights into this fundamental area of musical thought, the time seems right to tackle this complex topic.