The following bibliography is comprehensive but by no means complete.¹ With the exception of selected works on and by Hertz's teacher Helmholtz, each item in the bibliography relates directly, though not always extensively to Hertz's work. A key is provided to help users decide the relevance of an item. The attempt was made to include everything but the purely incidental, such as brief obituaries or commemorations in the popular press. Preference is given to English editions. The bibliography is current as of January, 1997.²