Are formal methods the answer?

Formal methods are commonly mentioned in connection with the analysis and design of computer systems and particularly critical systems. Given this rising interest it is appropriate to take a careful look at formal methods in order to determine if they are really worth this attention. The author defines `formal method´ and goes on to outline the benefits of formal notations for systems analysis. He also looks at the drawbacks of formal methods and proposes a framework for the optimal design of such a method