On 1994 July 27, the Burst and Transient Source Experiment (BATSE), on board the Compton Gamma-Ray Observatory (CGRO), detected an outburst of high energy X-rays from a previously unknown source toward the constellation of Scorpius [Harmon et al. 1995]. The source was designated GRO J1655-40.
Approximately 12 days after the X-ray outburst, a strong outburst at radio wavelengths occured [Campbell-Wilson & Hunstead 1994]. Given that Mirabel and Rodriguez [1994] had observed apparent superluminal motions following a similar outburst in another Galactic X-ray source, GRS 1915+105, with VLA observations, the radio outburst from GRO J1655-40 prompted radio astronomers to begin monitoring the source structure with synthesis arrays at arcsecond and mas resolutions.
Following observations of GRO J1655-40 with the SHEVE array, the aims of this chapter are:
1] To describe the SHEVE observations of GRO J1655-40, paying particular attention to the rapid structural evolution of the source and the problems for data reduction caused by this evolution.
2] To interpret the VLBI observations, to review other observations, and to review theoretical interpretations for GRO J1655-40.
The observations are described in 
6.2. The rapid evolution of the radio source and the problems in the data reduction caused by these effects are also described in 6.2. The final results and interpretation of the SHEVE data are given in 6.3. Finally in 6.4, a brief review of observations of this object made at other wavelengths and several theories for the nature of the Galactic superluminal sources, which have been presented since the discoveries of GRS 1915+105 and GRO J1655-40, are briefly reviewed.