From the World Wide Web to the electrical grid, networks are notoriously difficult to control. A disturbance to just one part of the system can spread quickly and affect the whole thing. But this problem is its own solution: by selectively damaging part of the network, we can bring the entire system to a better state.
Why is it so important to manipulate networks? These complex systems pervade our everyday lives, from telecommunications systems to the connected neurons that form memories in your brain.
Unfortunately, nudging just a few nodes of a network can cause the entire system to malfunction. Take the electrical grid: A few downed power lines can trigger widespread blackouts. And it takes a lot of work and expensive materials to fix the broken components.