Measurements over the last decade have revolutionized our understanding of (1) the heliosphere’s boundaries formed through the interactions with the interstellar neighborhood, (2) the acceleration and transport of solar and heliospheric suprathermal and energetic particle populations, and (3) the properties of the shocked solar wind, its embedded magnetic fields and convected interplanetary disturbances that impact geospace in the inner heliosphere. 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 the Interstellar Mapping and Acceleration Probe (IMAP) mission as the next and highest priority science target for the Solar Terrestrial Probes mission line. This session solicits relevant observational results, especially from IBEX, Voyager, Cassini, New Horizons, ACE and STEREO, that provided these breakthroughs and related theoretical efforts making specific predictions and raising outstanding open questions for developing a more complete picture in all three science areas targeted by IMAP.