The papers in this special issue comprise a selection of papers from the IEEE/OSA Journal of Lightwave Technology (JLT) from 1983-2016. This selection is based on various citation and journal metrics analyses. For a third of a century, the JLT has been publishing breakthrough research across all aspects of guided-wave optical science, technology, engineering, and applications, including theoretical, numerical, and experimental results from laboratory setups to field trials. Considered by many as the premier journal in this field, and consistently ranking near the top by various comparative journal metrics, JLT has covered optical fiber and cable technologies, active and passive guided-wave componentry (sources, detectors, repeaters, switches, sensors, etc.), integrated optics and optoelectronics, subsystems, systems and networks, as well as new applications related to guided-wave technologies.