Starting with basic physics, this monograph is written in 12 chapters and covers: laser beam propagation in atmosphere and effects like molecular absorption and scattering, random refraction and dispersion affecting intensity and collimation; laser sources like solid state and OPO, gaseous, semiconductors; optical resonators used for better beam quality and frequency stability are discussed; pumping/excitation of laser materials and cooling devices; Q-switching techniques like mechanical, electro-optics and passive elements for generation of giant pulse; electronics, optics and thin film technology including fabrication and specifications of critical components used in range finders; photo multiplier, avalanche photodiodes, MCT and InSb detectors are described for laser echo detection; design of ranging system, including assembly and testing, recent development; laser safety and precautions for operation and maintenance of ranging systems (318 pages, 248 references, 133 figures and 21 photos).