  The Interplanetary Network (IPN) is a detection, localization and alert
system that utilizes the arrival time of transient signals in gamma-ray
detectors on spacecraft separated by planetary baselines to geometrically
locate the origin of these transients. Due to the changing astrophysical
landscape and the new emphasis on time domain and multi-messenger astrophysics
(TDAMM) from the Pathways to Discovery in Astronomy and Astrophysics for the
2020s, this Gamma-ray Transient Network Science Analysis Group was tasked to
understand the role of the IPN and high-energy monitors in this new era. The
charge includes describing the science made possible with these facilities,
tracing the corresponding requirements and capabilities, and highlighting where
improved operations of existing instruments and the IPN would enhance TDAMM
science. While this study considers the full multiwavelength and multimessenger
context, the findings are specific to space-based high-energy monitors. These
facilities are important both for full characterization of these transients as
well as facilitating follow-up observations through discovery and localization.
The full document reports a brief history of this field, followed by our
detailed analyses and findings in some 68 pages, providing a holistic overview
of the role of the IPN and high-energy monitors in the coming decades.
