In the drive towards providing massive levels of electrical power through the agency of solar ray gathering, concentrated solar power (CSP) techniques offer potentially the most efficient, cost-effective solutions. These techniques are largely based on solar reflectors of one form or another, and several geometries are examined in this chapter. Four CSP options are currently receiving major attention by the power-generating industries. These are systems based on the use of parabolic troughs, linear Fresnel reflectors, heliostats and parabolic dishes. To assist in assessing these alternative schemes, we initially consider in Chap. 8 the relationship between an optical receiver and an antenna, and this leads to the introduction of ray optics as a design tool for large optical reflectors. In power collection terms, an optimum level of ray concentration is shown to exist in theory, and this knowledge provides useful pointers towards the design of efficient collectors. Also, at highpower concentration levels, optical reflectors are subject to thermal effects and the thermodynamics required to comprehend the relevant phenomena are presented in Sect. 8.3.