Daylight responsive lighting controls have great potential for energy savings and electric load management as well as improving the indoor work environment. While the concepts have been understood for some time and some systems are commercially available they have not yet reached the level where they are routinely specified, nor can they be counted on to deliver reliable savings. Dr. Choi has been exploring this field for some time, initially as a doctoral student at Penn State, then as an Assoc. Professor at Sejong University and now on sabbatical at LBNL. He will provide an overview of the key system elements (ballasts, photosensors, control software), define the performance requirements and illustrate the challenges that current systems have in meeting them. He will explain his recent work in developing better tools and software to predict energy savings, calibrate sensor systems, design solutions that will maintain proper target light levels and allow a sensor to be used to control multiple dimming zones. He will conclude by exploring future directions for research in this field.