Gamma ray energy tracking is a new concept for detecting gamma rays. It can be implemented as a 4&pgr; array of highly segmented Ge detector, which would advance detection sensitivity by three orders of magnitude in certain applications. Such an array will provide tremendous discovery potential at current stable and exotic beam facilities, as well as at future facilities. The development of a tracking array for nuclear structure physics has brought together scientists from different areas. Technical advances made in the last 5 years have demonstrated that the construction of a gamma ray energy‐tracking array is feasible, and a plan for constructing a US array is in place. © 2003 American Institute of Physics