  The PHANGS collaboration has been building a reference dataset for the
multi-scale, multi-phase study of star formation and the interstellar medium in
nearby galaxies. With the successful launch and commissioning of JWST, we can
now obtain high-resolution infrared imaging to probe the youngest stellar
populations and dust emission on the scales of star clusters and molecular
clouds ($\sim$5-50 pc). In Cycle 1, PHANGS is conducting an 8-band imaging
survey from 2-21$\mu$m of 19 nearby spiral galaxies. CO(2-1) mapping, optical
integral field spectroscopy, and UV-optical imaging for all 19 galaxies have
been obtained through large programs with ALMA, VLT/MUSE, and Hubble.
PHANGS-JWST enables a full inventory of star formation, accurate measurement of
the mass and age of star clusters, identification of the youngest embedded
stellar populations, and characterization of the physical state of small dust
grains. When combined with Hubble catalogs of $\sim$10,000 star clusters, MUSE
spectroscopic mapping of $\sim$20,000 HII regions, and $\sim$12,000
ALMA-identified molecular clouds, it becomes possible to measure the timescales
and efficiencies of the earliest phases of star formation and feedback, build
an empirical model of the dependence of small dust grain properties on local
ISM conditions, and test our understanding of how dust-reprocessed starlight
traces star formation activity, all across a diversity of galactic
environments. Here we describe the PHANGS-JWST Treasury survey, present the
remarkable imaging obtained in the first few months of science operations, and
provide context for the initial results presented in the first series of
PHANGS-JWST publications.
