Over the last decade measurements from Voyager, IBEX, and Cassini have revolutionized our understanding of the heliosphere’s boundaries and their interactions with the interstellar neighborhood. At the same time, ACE, Wind, SoHO, and STEREO have provided new insights into (1) the acceleration and transport of solar and heliospheric particle populations, and (2) the properties of the solar wind and the embedded magnetic field and interplanetary disturbances that impact geospace. Simultaneously, TWINS used ENAs to uniquely probe the global responses of the Earth’s magnetosphere to solar and interplanetary disturbances. In view of theses successes, the US National Research Council’s 2012 Solar and Space Physics Decadal Survey recognized the critical need to urgently make progress in all three areas simultaneously, and recommended that NASA implement the Interstellar Mapping and Acceleration Probe (IMAP) mission as the next and highest priority science target for the Solar Terrestrial Probes (STP) mission line. This session solicits relevant theoretical considerations, numerical simulations, observational results from IBEX, Voyager, near-Earth satellites, and TWINS that have led to tremendous breakthroughs, and related theoretical efforts that make specific testable predictions for developing a more complete picture in all three science areas targeted by IMAP.