The Nobel Prize in Chemistry was awarded in 2000 for the discovery anddevelopment of conducting polymers. This event gives an opportunity to review the two decades of intensive research in this field. The electronically and optically active conjugated polymers are still looking for their place as an interdisciplinary science, while their possession is disputed between fundamental studies and applications, chemistry and physics, molecular and condensed matter physics, quantum chemistry and solid state theory.We shall outline advantages of applying the principles of the solid state theory to electronic and optical properties of conducting polymers. We pay special efforts to bring together the languages of the solid state physics for polymers and the quantum chemistry of oligomers. A part of the talk will be devoted to optics of linear polymers, the story of solitons, intragap states, and their experimental manifestations. The second part will address the physical grounds for most important contemporary applications of the polymers: linear and nonlinear optics, junctions including the field induced superconductivity, etc.