Classic epistemic logic focuses on propositional knowledge (in terms of ""knowing that P""). However, various forms of knowledge are used in everyday life, which suggest non-standard but interesting new epistemic operators. In this course, I survey the recent line of work on modal logics based on ""knowing whether"", ""knowing what"" and ""knowing how"" operators. These new logics are not normal modal logics due to the lack of standard modal axioms, which require new techniques to handle. I will focus on the axiomatizations of such epistemic logics but will also cover issues such as decidability, definability and technical/philosophical comparisons between them and the classic epistemic logic.