The VISTA Deep Extragalactic Observations Survey (VIDEO) is a 15 square degree Z, Y, J, H, Ks survey to study galaxy evolution as a function of epoch and environment to redshift of ∼4 using active galactic nuclei, galaxy cluster evolution, and very massive galaxies. The survey comprises four fields: the Chandra Deep Field South, 4.5 square degrees of the XMM-Newton Large-Scale Structure Survey, a field of the European Large-Area ISO Survey, and a new field. The width and area of VIDEO are intermediate between the wide but relatively shallow VIKING survey and the small, but very deep, Ultra-VISTA.