LMC X-3 IS UNIQUE AMONG STELLAR BLACK HOLES IN THAT IT IS A TRANSIENT SYSTEM (VARYING BY ORDERS OF MAGNITUDE IN INTENSITY) AND YET IT IS ALSO PERSISTENTLY BRIGHT AND NEARLY ALWAYS IN A VERY SOFT THERMAL STATE. BY VIRTUE OF ITS EXTREME THERMAL DOMINANCE IT IS THE IDEAL SYSTEM WITH WHICH TO EXAMINE THE STRUCTURE OF THE THERMAL DISK. NICER AND NUSTAR OFFER A UNIQUELY POWERFUL CAPABILITY IN THIS RESPECT TO EMPIRICALLY ESTABLISH THE STRUCTURE OF SLIM DISKS THROUGH MONITORING THAT PROBES LUMINOSITY VARIATIONS IN THE SYSTEM.