I propose a set of criteria which distinguish a grand challenge in science or engineering from the many other kinds of short-term
or long-term research problems that engage the interest of scientists and engineers. As an example drawn from Computer Science,
I revive an old challenge: the construction and application of a verifying compiler that guarantees correctness of a program
before running it.
Reprinted with the kind allowance of Springer Verlag from the proceedings of ECOOP 2003, LNCS 2743