1. Introduction
2. Data and Photometry
2.1. The Sample of Cepheid Variables
2.2. Observations and Data Reduction
2.3. Photometry
3. Optical and Near-IR Light Curves of Cepheid Variables
3.1. Pulsation Periods and the Phase-binned Light Curves
3.2. Light Curve Fitting and Mean Magnitudes
3.3. Period-Amplitude Diagrams
4. Absolute Calibration of the Leavitt Law
4.1. Gaia Parallaxes
4.2. Reddening and Extinction Corrections
4.3. Period–Luminosity Relations
4.4. Period-Wesenheit Relations
4.5. Comparison with Literature
5. Metallicity Dependence of the Leavitt Law
5.1. Comparison of Residuals of PL and PLZ Relations
5.2. Metallicity Coefficient as a Function of Wavelength
6. Summary