  Commonly used techniques to study non-perturbative aspects of the strong
interactions have a deep connection with rational approximants, and in
particular with Pad\'e approximants to meromorphic functions. However, only
recently this connection has been acknowledged and efforts at fully exploiting
it are only starting. In this article I will briefly review the most prominent
techniques used in non-perturbative strong interactions with special emphasis
on its relation with Pad\'e approximants. I will then concentrate on a set of
open problems outside the scope of these conventional techniques where Pad\'e
approximants might be extremely useful.
