This Atlas and Catalog collects the main data products of the S4G project, including deep mid-IR imaging; total mid-IR magnitudes and color indices; mid-IR isophotal and effective diameters and axis ratios; bulge, disk, and bar scale lengths, characteristic surface bright nesses, and fractional contributions to the total luminosity; and auxiliary data from other sources, such as optical and UV magnitudes and colors, radial velocities, and distance estimates. The quantitative mid-IR parameters will be taken from the various publications of the S4G team, and will be included with appropriate references. Other parameters will be gathered from other published sources.