THE SCIENCE OF GAMMA RAY BURSTERS has now advanced to the point where a robot optical telescope, responding to signals from orbiting gamma-ray and x-ray telescopes, can within seconds swivel to a spot on the sky and photograph the visible component of the burst. Thus the object GRB990123 (with a redshift of 1.6) was glimpsed at optical wavelengths on January 23, 1999 at the crucial early stage of its eruption. Indeed this was the first time a GRB was detected optically while still belting out gammas. Judging by its gamma emissions it was either the most energetic GRB yet observed (if its energy were being spewed the same in all directions) or the observations constitute the first evidence for a beaming effect in GRB's. The object's afterglow was also watched by radio and infrared telescopes. These prompt measurements are important for understanding the burster's energy engine, which operates at full throttle for only about 100 seconds. (Science, 26 March 1999; Nature, 1 April 1999.)