This book is an introduction to this young branch of optics. It is divided into two sections: the fi rst one deals with nonimaging optics—its main concepts and methods. The second section is a summary of the general concepts of geometrical optics and some other topics. Although the fi rst section is meant to be complete by itself, many general concepts have a different usage in nonimaging optics than in other branches of optics. That is why the second part may be very useful by explaining those concepts from the perspective of nonimaging optics. It is, therefore, a part of the book that the reader can refer to while reading the fi rst section, should some concepts seem obscure or used differently from what he or she is used to.