Nonimaging Optics is the theory of thermodynamically efficient optics and as such depends more on thermodynamics than on optics. Hence, I propose a condition for the best design based on purely thermodynamic arguments, which I believe has profound consequences for design of thermal and even photovoltaic systems. This new way of looking at the problem of efficient concentration depends on probabilities, the ingredients of entropy, and information theory while optics in the conventional sense recedes into the background. The paper takes a pedagogical and retrospective approach, as to place the new approach in perspective, it helps to first appreciate what has succeeded in nonimaging optics, and turned some devices [e.g. the compound parabolic concentrator (CPC) cone] into a commodity. I will conclude with some speculative directions on where the new ideas might lead.