Geometric-phase microscopy (GPM) uses changes in the phase of light passing through biological specimens to yield high-resolution and high-contrast images, instead of relying on the attenuation of light used conventionally. Polarization optics and a spatial light modulator generate spatially variant polarization states of light that interact with the sample, creating a relative phase shift between transmitted and reflected light waves. By analyzing the phase information, GPM can reveal details not visible with other microscopy techniques. GPM is an effective non-invasive tool for live cell and tissue studies, with potential to enhance biological systems knowledge.