  One of the last remaining frontiers in optical/near-infrared observational
astronomy is the low surface brightness regime (LSB, V-band surface brightness,
$\mu_V>$ 27 AB mag/arcsec$^2$). These are the structures at very low stellar
surface densities, largely unseen by even current wide-field surveys such as
the Legacy Survey. Studying this domain promises to be transformative for our
understanding of star formation in low-mass galaxies, the hierarchical assembly
of galaxies and galaxy clusters, and the nature of dark matter. It is thus
essential to reach depths beyond $\mu_V$ = 30 AB mag/arcsec$^2$ to detect the
faintest extragalactic sources, such as dwarf galaxies and the stellar halos
around galaxies and within galaxy clusters. The High Latitude Wide Area Survey
offers a unique opportunity to statistically study the LSB universe at
unprecedented depths in the IR over an area of $\sim$2000 square degrees. The
high spatial resolution will minimize source confusion, allowing an unbiased
characterization of LSB structures, including the identification of stars in
nearby LSB galaxies and globular clusters. In addition, the combination of
Roman with other upcoming deep imaging observatories (such as Rubin) will
provide multi-wavelength coverage to derive photometric redshifts and infer the
stellar populations of LSB objects.
