Large technical systems (LTS) are huge implements, and the public debates of the past decade or so around what is vaguely called “Big Technology” echo the age-old concern with the proper limits to the size of things. LTS are exposed as a distinct type of technical system, and some conjectures as to their peculiar dynamics are offered. The history of the emergence of large corporate organizations is inextricably linked to the large technical structures they have built up, as evidenced by A. D. Chandler’s, Louis Galambos’s and Stephen Salsbur’s work. Only opening up the historian-of-technology’s perspective to ever larger “non-technical” contexts has allowed Hughes to embrace the complexity of evolving LTS such as, nationwide integrated electricity generation, but also other powerful networks. The chapter considers technical systems as systems of machineries and freestanding structures performing, more or less reliably and predictably, complex standardized operations by virtue of being integrated with other social processes, governed and legitimated by formal, impersonal rationalities.