In the long term, innovations in software engineering are likely to bring dramatic improvements in dependability. Software systems are complex and, just as in other sorts of complex systems, failures will inevitably occur. But if our society succeeds in this ambitious program, we can hope that, 10 or 20 years from now, the adoption of ambitious and potentially dangerous new systems will be justified by rational arguments; a broad consensus in the software industry will guide standard practice; the production of software will be less expensive and more predictable than it is today; and the incidence of software failures will be low and well-documented.