A half century after its invention, and after several waves of optimism and pessimism, holography is now poised to achieve widespread application. Holograms are now being used as tools in many industries, from heads-up displays in aircraft to directing interconnections in massively parallel computing. Acoustic holograms can provide three-dimensional images of internal organs without surgery or dangerous radiation, and holography forms the basis of several other forms of nondestructive testing. This book provides both a review of the development of the field and of the applications likely to be important in the 21st century. It begins with a review by Emmett Leith, one of the inventors of holography - or re-inventors, after Denis Gabor's original work in 1947. Two chapters discuss the frontiers of holographic imaging, including color holograms and stereographic movies. Several subsequent chapters describe novel methods of forming and viewing holographic images, including the use of low-coherence sources or even computers to generate the holograms. The book concludes with a sampling of new applications of holography, including its uses in improving the efficiency of solar cells, in nondestructive testing, in improving the coherence properties of light, in data storage, and in investigations of fundamental physics.