  Hierarchical models of galaxy formation predict that galaxy mergers represent
a significant transitional stage of rapid supermassive black hole (SMBH)
growth. Yet, the connection between the merging process and enhanced active
galactic nuclei (AGN) activity as well as the timescale of SMBH mergers remains
highly uncertain. The breakthrough in reconciling the importance of galaxy
mergers with black hole growth lies in a thoroughly-studied census of dual AGN
across cosmic history, which will be enabled by next-generation observational
capabilities, theoretical advances, and simulations. This white paper outlines
the key questions in galaxy mergers, dual and offset AGN, and proposes
multiwavelength solutions using future high-resolution observatories in the
X-rays (AXIS, Lynx), near and mid-infrared (30 meter class telescopes, JWST),
and submillimeter (ALMA).
