The previous chapter focused on the essential ideas of the Perfect Lens. The perfect lens is an ideal imaging device that requires ideal materials with ε = μ = −1 for image resolution without limit. It was shown that very small deviations of the material parameters from these ideal conditions could lead to the excitation of resonances that cause deterioration of the performance of the lens. In addition, ﬁnite amounts of dissipation and other imperfections that occur in actual materials have been shown to also limit the resolution of this device. Substantial subwavelength resolution is, however, possible in spite of dissipation, and the lenses exhibiting some degree of subwavelength image resolution capabilities have been termed Super-Lenses.