The scientific value of the collection of physiological-optical works printed below does not require further discussion at this point. No one can deny that it secures Arthur König an honorable place among the promoters of the most important and challenging problems in the physiology of vision. The essays are printed in chronological order, which facilitates insight into the development of König's investigations and views. This book presents the collected papers on physiological optics and is an unaltered reprint of the original edition from 1903. Illustrated with over 40 historical images. The Verlag der Wissenschaften publishes historical literature by well-known and lesser-known scientific authors, thereby making works that have long been out of print accessible to interested readers once again.