  The Daniel K. Inouye Solar Telescope (DKIST) Visible Spectro-Polarimeter
(ViSP) is a traditional slit-scanning spectrograph, with the ability to observe
solar regions up to a $120\times78~\mathrm{arcsec}^2$ area. The design
implements dual-beam polarimetry, a polychromatic polarization modulator, a
high-dispersion echelle grating, and three spectral channels that can be
automatically positioned. A defining feature of the instrument is its
capability to tune anywhere within the 380-900~nm range of the solar spectrum,
allowing for a virtually infinite number of combinations of three wavelengths
to be observed simultaneously. This enables the ViSP user to pursue
well-established spectro-polarimetric studies of the magnetic structure and
plasma dynamics of the solar atmosphere, as well as completely novel
investigations of the solar spectrum. Within the suite of first-generation
instruments at the DKIST, ViSP is the only wavelength-versatile
spectro-polarimeter available to the scientific community. It was specifically
designed to be a discovery instrument, for the exploration of new spectroscopic
and polarimetric diagnostics, and to test improved models of polarized line
formation, through high spatial-, spectral-, and temporal-resolution
observations of the Sun's polarized spectrum. In this instrument article, we
describe the science requirements and design drivers of ViSP, and we present
preliminary science data collected during the commissioning of the instrument.
