  The James Webb Space Telescope's Near Infrared Imager and Slitless
Spectrograph (JWST-NIRISS) flies a 7-hole non-redundant mask (NRM), the first
such interferometer in space, operating at 3-5 \micron~wavelengths, and a
bright limit of $\simeq 4$ magnitudes in W2. We describe the NIRISS Aperture
Masking Interferometry (AMI) mode to help potential observers understand its
underlying principles, present some sample science cases, explain its
operational observing strategies, indicate how AMI proposals can be developed
with data simulations, and how AMI data can be analyzed. We also present key
results from commissioning AMI. Since the allied Kernel Phase Imaging (KPI)
technique benefits from AMI operational strategies, we also cover NIRISS KPI
methods and analysis techniques, including a new user-friendly KPI pipeline.
The NIRISS KPI bright limit is $\simeq 8$ W2 magnitudes. AMI (and KPI) achieve
an inner working angle of $\sim 70$ mas that is well inside the $\sim 400$ mas
NIRCam inner working angle for its circular occulter coronagraphs at comparable
wavelengths.
