Technicolor

Technicolor, with extended technicolor, is the theory of dynamical electroweak and flavor symmetry breaking at energies far below the Planck scale. To motivate it, I describe the most important difficulties of the standard electroweak model of symmetry breaking by elementary scalar bosons. I then tell how technicolor deals with these difficulties in a way that is both technically and physically natural. Finally, I discuss the problems of technicolor, both past and present. (This is the written version of an invited talk given at the International Conference on the History of Original Ideas and Basic Discoveries in Particle Physics, Erice, Sicily, 29 July--4 August 1994.)