I wish to learn about Epistemic Modal Logic in a way that's rigorous yet easy$\color{red}{^1}$ to understand. Could you recommend books, courses, or any other relevant resources I could look into?
I have a background in Set Theory, Propositional Logic, First-order Logic, and Basic Modal Logic (I am familiar with the basic modal language, models, model constructions, frames, completeness, etc. My primary reference for this has been Blackburn's Modal Logic - the first four chapters). Happy to provide any other detail necessary.
$\color{red}{1.}$ By "easy", I mean something suited for undergraduate math majors. This isn't a hard requirement though - I am open to all kinds of recommendations!
P.S. Since this question is really specific to Epistemic Logic, in all probability it is not a duplicate.