Electronic holographic imaging, developed at the MIT Media Laboratory Spatial Imaging Group over the past five years, is a truly three-dimensional real-time digital imaging medium. Recent work in holographic video has demonstrated that the crucial technologies -- computation, electronic signal manipulation, and optical modulation and scanning -- may be scaled up to produce larger, more interactive, full-color holographic images. Synthetic images and images derived from real-world scenes are quickly converted into holographic fringe patterns using newly-developed `diffraction-specific' computational algorithms. A parallel- architecture signal processing system distributes the holographic video among multiple output boards. To diffract light so as to form an image in real time, the display employs an 18- parallel-channel, scanned, time-multiplexed acousto-optical modulator. The successful scaling- up of the MIT holographic video system has depended on the application of the concepts of electronic and optical parallelism at every stage.