This article reviews the R&D activities in few-mode fibers, a special class of multimode optical fibers, beginning with its original motivation in the late 1970s, the operation principles, and the reason why research was discontinued in the mid-1980s. Preliminary characterizations of the test few-mode fiber fabricated for the first time are also introduced. Besides the earlier works, we review the progress of few-mode fibers after the resurgence of research in the 2010s on optical transmission and networking through mode-division multiplexing and other emerging applications. Recent revisiting of few-mode fibers is totally different from the original motivation, and it is mainly to solve the capacity crunch problem of optical fiber transmissions using legacy single-mode fibers. We address difficult challenges current research on mode-division multiplexing is facing, including differential mode group delay, channel crosstalk due to mode coupling, and their compensation technique through multiple-input multiple-output electronic signal processing. We also address the general perspective of niche applications in the near future. Such a revisit of few-mode fibers after its invention more than 30 years ago deserves showcasing for those engaged in research and development today to show how all research can eventually prove to be important no matter if it finds practical usage for different purposes in the beginning or not, as well as how people can work out a certain problem in many different ways.