Linked from
The 14 pages that link to Holography, each with the reason it gives.
InterferenceRelated: A reference beam interferes with reflected light to encode a hologram.
Wave opticsRelated: It stores phase information that ordinary intensity photography discards.
Coherence (physics)Related: Recording a stable interference pattern requires coherent illumination.
Helium–neon laserRelated: Its coherent red beam can illuminate holographic recording setups.