As we approach the half century mark for the dawn of the era of optical communications, it is appropriate to take stock of the journey of discovery and application of this empowering technology. As with most new technologies, the engineering challenges associated with its assimilation into the existing infrastructure have been as significant as the scientific advances within the invention of the laser itself. ITU-T has been active in the standardization of optical communications technology and the techniques for its optimal application within networks from the infancy of this industry. However, it is not always easy to find out what has been covered, and where it can be found. This manual attempts to aggregate all of the available information on ITU-T’s work.