The technologies and advances in the field of three-dimensional (3D) displays within the past two decades are reviewed. Specifically, the developments in diffractive, refractive, reflective and occlusive 3D display strategies are discussed, highlighting the advantages and limitations of the associated systems. The partial pixel and the partial object pixel architectures associated with autostereoscopic displays are discussed in some detail, while other techniques are briefly introduced. It is shown that major breakthroughs occurred with the development of computer-generated holography (CGH), liquid crystal arrays (LCA) and other spatial light modulators (SLM), and also the discrete fabrication of diffractive and holographic optical elements (DOE and HOE), micromirror arrays, and microelectromechanical systems (MEMS). These techniques and components have enabled the implementation of spatially and angularly multiplexed 3D images and scenes with potentially dynamic (time-varying) features.