The role of the detector in optical spectroscopy has evolved over the years, as advances in technology, driven by application requirements, have made the detector much more than simply a transducer at the end of an optical arrangement. Earlier instruments generally consisted of a relatively high-cost spectrometer and a low-cost detector such as a Photomultiplier Tube (PMT). Thus, the detector was an accessory to the spectrometer. As detector technologies improved, the capability, complexity and expense of the detector increased, placing a lower emphasis on the capabilities of the spectrometer, whose design and capabilities remained relatively constant during the same time period. Today, many researchers accept the notion that the detector is the heart of a spectroscopic system, and the optical subsystem is more of an accessory to the detector. The evolving role of the detector, from an accessory to a key component, was driven by rapid advances in technology as well as cost reduction of complex technologies. In many cases, modern spectroscopic instruments are designed as an integrated system in which the detector is an integral part of the spectrometer or spectrograph, making it possible to optimize the spectroscopic system performance at even lower cost. In this Article, we discuss some common detector choices, their roles in the spectroscopic detection arena, and salient points related to selection, advantages and key performance metrics. Examples of HORIBA Jobin Yvon, Inc. detector products and technologies are provided to illustrate sample implementations that address common application requirements.