Catoptrics deals with the phenomena of reflected light and image-forming optical systems using mirrors. From the Greek κατοπτρικός (specular)[1].
The book Catoptrics attributed to Euclid[2] covered the mathematical theory of mirrors, particularly the images formed by plane and spherical concave mirrors.
The first practical catoptric telescope (the "Newtonian reflector") was built by Isaac Newton as a solution to the problem of chromatic aberration exhibited in telescopes using lenses as objectives (dioptric telescopes).