Software that matches its specifications perfectly and has perfect specifications may be used erroneously by users. Thus the question of how good is good enough relates to when to release the software, and also how to safeguard the actors from the inevitable errors. American Telegraph & Telephone (AT&T) controls carriers for the world’s largest communication system. In January 1990, AT&T experienced a massive system failure that crippled its ability to carry longdistance communication. Rawls generates a theory for rules of conduct in a society with the knowledge that the participants of society interact with one another in cooperation and in conflict. A provider can be a software manufacturer or an individual programmer. A user can be a programmer using a compiler, a secretary using a word processor, a pilot using a fly-by-wire system, or engineers in a nuclear power plant. The software profession has been struggling with problems of software quality since the time of Lady Lovelace and Charles Babbage.