The age of large space optical systems began in the early 1960s. With very little precedent but driven by necessity, there emerged a series of new mechanical and structural technologies including dramatically lightweighted mirrors, ultra-stable low thermal expansion structures, large-scale testing thermal and vacuum environment testing, and robust alignment sensing and control systems. We will review in this monograph the growth of these and other technologies, beginning with a heritage that had its origins in amateur telescope making. We will also address a newer design technology, design-to-cost, which has become a dominant system discriminator in the past decade. This is not intended as a how-to technical paper. Instead it is intended to surface some of the questions and considerations that need to be answered in the development of any new systems concept, rather like a checklist, to ensure that low cost and a high probability of initial success are achieved.