  Justification logics are epistemic logics which allow knowledge and  belief modalities to be ‘unfolded’ into justification terms: instead of \(\Box X\) one writes  \(t : X\), and reads it as “\(X\) is justified by reason \(t\)”. One may think of traditional modal  operators as implicit modalities, and justification terms as their explicit elaborations which supplement modal logics  with finer-grained epistemic machinery. The family of justification  terms has structure and operations. Choice of operations gives rise  to different justification logics. For all common epistemic logics  their modalities can be completely unfolded into explicit  justification form. In this respect Justification Logic reveals and  uses the explicit, but hidden, content of traditional Epistemic Modal Logic.