There was a time, in the distant past, when technology mainly took the form of simple tools, each used for a particular purpose. But technology gets more complicated as it advances. The simple tools become more elaborate, and they begin to merge into ever more complex systems. Today, a lot of the products that companies produce are components of much larger systems, and the success of those products can hinge as much on the other components of the systems as on their own particular qualities. Making sense of the systems and, in particular, how they’re likely to evolve can give a company a big advantage over less insightful competitors.

But making sense of technological systems is hard.

One of the best ways to think about how such systems progress is through the idea of “reverse salients.” The great technology historian Thomas P. Hughes introduced the phrase, in the context of technological innovation, is his book on the development of electric power systems, Networks of Power. He borrowed the term from military jargon, where it referred to a section of an advancing force that falls behind the front and hence slows the progress of the attack. Technological systems, he showed, advance in a similar way. Progress is held up when a reverse salient forms in some component or subsystem, but then begins again when the problem is solved – until the next reverse salient forms.

In my new column on business innovation for Strategy & Business, “The Weakest Link,” I describe how the idea of reverse salients can also help companies make smart decisions about where to invest in innovation and where to look for competitive advantage. The article begins with the story of how a tiny strip of rubber played a crucial role in determining the course of modern aircraft design.