Recently there is an increasing interest in tailored optical fields with complex amplitude, phase and polarization spatial distributions, as well as specifically designed temporal waveforms. Scalar optical vortices carrying orbital angular momentum and vectorial vortices such as radially and azimuthally polarized beams are among the most intensively studied examples. Comprehensive summaries of earlier developments can be found in several recent articles and edited books, e.g., by Zhan (Adv. Opt. Photon.1, 1, 20091943-8206), Padgett (Adv. Opt. Photon.3, 161, 20111943-8206 ), Forbes (Adv. Opt. Photon.8, 200, 20161943-8206), Zhan (Vectorial Optical Fields, World Scientific Publishing, 2013), and Forbes (Laser Beam Propagation, CRC Press, 2014), while applications of these complex optical fields in promising areas continue to emerge. To capture the latest developments in this important emerging field of optics, it is our pleasure to introduce the Chinese Optics Letters Special Issue on the Complex Optical Fields with contributions from scientists around the world who are active in this field.