At the core of evidentialism lies a very plausible claim: rational thinkers follow their evidence. While this seems to be a very intuitive, almost trivial, claim, providing a full and complete evidentialist theory is complicated. In this entry, I begin with elucidating what kind of theory evidentialists aim to provide us with. I will show that, in order to provide a complete evidentialist theory, we have to provide a lot of details on what evidence is and how it relates to (...) the proposition it’s evidence for, as well as the agent possessing such evidence. I then consider objections arising for the most popular answers one can give to such questions. I conclude by considering old and new challenges that arise for evidentialism, regardless of the specific version one endorses. (shrink)